GB2483942A - Electric lamp - Google Patents

Electric lamp Download PDF

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Publication number
GB2483942A
GB2483942A GB1020452.7A GB201020452A GB2483942A GB 2483942 A GB2483942 A GB 2483942A GB 201020452 A GB201020452 A GB 201020452A GB 2483942 A GB2483942 A GB 2483942A
Authority
GB
United Kingdom
Prior art keywords
lamp
light sources
members
skeleton
axis
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Withdrawn
Application number
GB1020452.7A
Other versions
GB201020452D0 (en
Inventor
Nigel Alastair Dent
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zeta Controls Ltd
Original Assignee
Zeta Controls Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Zeta Controls Ltd filed Critical Zeta Controls Ltd
Priority to GB1020452.7A priority Critical patent/GB2483942A/en
Publication of GB201020452D0 publication Critical patent/GB201020452D0/en
Publication of GB2483942A publication Critical patent/GB2483942A/en
Withdrawn legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21VFUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V29/00Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/50Cooling arrangements
    • F21V29/70Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks
    • F21V29/83Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks the elements having apertures, ducts or channels, e.g. heat radiation holes
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21KNON-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
    • F21K9/00Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/20Light sources comprising attachment means
    • F21K9/27Retrofit light sources for lighting devices with two fittings for each light source, e.g. for substitution of fluorescent tubes
    • F21V29/004
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21KNON-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
    • F21K9/00Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/20Light sources comprising attachment means
    • F21K9/23Retrofit 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
    • F21K9/232Retrofit 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
    • F21Y2103/003
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21YINDEXING 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
    • F21Y2103/00Elongate light sources, e.g. fluorescent tubes
    • F21Y2103/10Elongate light sources, e.g. fluorescent tubes comprising a linear array of point-like light-generating elements
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21YINDEXING 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
    • F21Y2107/00Light sources with three-dimensionally disposed light-generating elements
    • F21Y2107/30Light sources with three-dimensionally disposed light-generating elements on the outer surface of cylindrical surfaces, e.g. rod-shaped supports having a circular or a polygonal cross section
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21YINDEXING 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
    • F21Y2115/00Light-generating elements of semiconductor light sources
    • F21Y2115/10Light-emitting diodes [LED]

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

Abstract

An electric lamp 10 has light sources 34, such as LEDs, an electrical connector 35 connected to the light sources and a structure to which the light sources 34 are mounted with different orientations and to which the connector 35 is mounted. The structure has the form of an open, three-dimensional skeleton of preferably metallic members 21 so that ambient air can circulate through the skeleton and around the members. The light sources are mounted in thermal contact with the members. The members are thermally conductive so that they can dissipate heat away from the light sources.

Description

TITLE
Electric lamps
DESCRIPTION
This invention relates to electric lamps. The invention was conceived while developing a low-energy' replacement for a conventional 60 Watt general lighting service (GLS') tungsten-filament light bulb. However, the invention is also applicable to many other general types of electric lamp.
It is well known that the light-producing efficiency of tungsten-filament bulbs is low and that light-emitting diodes (LEDs') can nowadays be produced having a far higher light-producing efficiency. However, despite producing significantly less heat than tungsten filament bulbs having the same light output, it is very important that the junction temperature of an LED is maintained below a limit value, otherwise the LED will immediately blow. Furthermore, even if an LED is operated with its junction below its limit temperature, its life expectancy decreases with increasing operating temperature. Moreover, the light-producing efficiency of LEDs decreases with increasing operating temperature.
It is also well known that a GLS bulb has a fairly uniform light radiation pattern over a very large angle, for example from 0 to 150 degrees or more relative to the axis of the bulb. By contrast, LEDs generally have a far smaller radiation angle unless special optics are provided.
Furthermore, the light output from a single commonly-available high-power LED is substantially less than from a 60 Watt tungsten-filament bulb.
One way of emulating a GLS tungsten-filament using LED technology would therefore be to mount a number of LEDs in a cluster with the LEDs pointing in different directions.
However, mounting the LEDs in a cluster increases the difficulty in dissipating heat from the LEDs so as to keep their junction temperatures low. Also, mounting a large number of LEDs in a cluster so that they face in different directions creates manufacturing difficulties.
An aim of the present invention, or at least of specific embodiments of it, is to produce an electric lamp which has a plurality of light sources oriented in different directions, which facilitates cooling of the light sources, and which can be manufactured relatively simply and inexpensively.
In accordance with the present invention, there is provided an electric lamp comprising: a plurality of electrically-powered light sources (for example LEDs); at least one electrical connector electrically connected to the light sources; and a structure to which the light sources are mounted with different orientations and to which the connector(s) is/are mounted. The invention is characterised in that: the structure has the form of an open, three-dimensional skeleton of members so that ambient air can circulate through the skeleton and around the members; the light sources are mounted in thermal contact with the members; and the members are thermally conductive so that they can dissipate heat away from the light sources.
By mounting the light sources on and in thermal contact with a thermally conductive skeleton, heat can readily be dissipated from the light sources, and by arranging the skeleton three-dimensionally, the light sources can conveniently be oriented in different directions.
The light sources are preferably substantially rigidly mounted on the members. The skeleton is preferably substantially rigid. At least some of the members of the skeleton are preferably formed of metal. At least some of the members of the skeleton are preferably integrally formed. These features result in a robust structure.
At least some of the members of the skeleton are preferably from an initially flat piece of material. At least some of the members of the skeleton may carry electrically-conductive tracks connecting at least in part the light sources to the electrical connector(s). Fitting the light sources to the flat piece of material before it is formed into the three-dimensional skeleton can simplify manufacture of the lamp.
In some embodiments of the invention, the light sources are substantially regularly arranged around the axis of the lamp. In some embodiments of the invention, the optical axes of all or at least one group of the light sources extend substantially at right angles to the axis of the lamp. In this case, the lamp can be arranged to emulate a tube light or festoon bulb.
Alternatively or additionally, the optical axes of all or at least a first group of the light sources lie substantially on a first common cone. In some embodiments, the axis of the first common cone is substantially coaxial with the axis of the lamp. In some embodiments, the optical axes of a second group of the light sources lie substantially on a second common cone substantially coaxial with the first common cone. With these features, the lamp can be arranged to emulate a GLS bulb or a spotlight.
The lamp is preferably devoid of an enclosure enveloping the skeleton and the light sources, so as not to hinder the circulation of air. When used with a lamp fitting, the lamp fitting is preferably also devoid of an enclosure enveloping the skeleton and the light sources of the lamp.
Specific embodiments of the present invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: Figures 1-9 show various stages in the manufacture of a first embodiment of electric lamp, with Figures 1-5 being plan views and Figures 6-9 being isometric views; Figure 10 is an isometric view of a former used in the manufacture of the electric lamp; Figure 11 is an isometric view of the completed electric lamp; Figure 12 is a side view of the electric lamp, cross-sectioned on its it right half; Figure 13 is a cross-sectioned end view of the electric lamp; Figures 14-18 are isometric views showing various stages in the manufacture of a second embodiment of electric lamp, Figure 19 is an isometric view of a former used in the manufacture of the electric lamp; Figure 20 is an isometric view of the completed electric lamp; Figure 21 is a side view of the electric lamp, cross-sectioned on its it right half; Figures 22-26 are isometric views showing various stages in the manufacture of a third embodiment of electric lamp; Figures 27-30 are isometric views showing various stages in the manufacture of a fourth embodiment of electric lamp; and Figure 31 is a sectioned side view of the fourth embodiment of electric lamp.
Referring to the drawings, in the manufacture of the first embodiment of electric lamp (Figures 11-13) emulating a conventional tube or festoon light bulb, a blank 12 (Figure 1) is employed comprising a flat sheet of aluminium having a thickness of, for example, 1 to 2 mm and to each face of which is bonded an electrically-insulating layer of, for example, Melinex® polyethylene terephthalate film. The blank 12 is cut to have a main rectangular portion 14 and a pair of smaller rectangular tabs 16 projecting from one edge 18 of the main portion 14 at the ends of that edge 18. Five equispaced main slits 20 are formed through the main portion 14 parallel to the edge 18 between the tabs 16 to divide the main portion into six parallel ribs 21.
The main slits 20 and the edge 18 are continued as dashed slits 22 at the ends of the main portion 14. A number of though-holes 24 are formed in the blank 12.
Referring to Figure 2, each through-hole 24 in the blank 12 is then lined with an electrically-insulating sleeve 26 of plastics material.
Referring to Figures 3A-B, which show the opposite faces of the blank 12, a number of copper tracks 28 are then formed on the insulating layers of the blank 12 in a required pattern.
The tracks 28 cover both ends of each of the lined holes 24 but do not cover any of the slits 20,22. The copper tracks 28 may be applied in any suitable manner, for example by blanking-out copper foil and bonding the pieces to the insulated blank 12, or by a foil blocking process.
Referring to Figure 4, a number of headed copper rivets 30 are then punched through the insulated through-holes 24 and the copper tracks 28 at either end of them, and the tails of the rivets 30 are upset so that the rivets 30 form vias electrically connecting the tracks 28 at each end of each hole 24.
Referring to Figures 5-6, the assembly of the circuit board 32 is completed by soldering a number of electrical components onto the blank 12. The components include surface-mount LEDs 34 which are connected between portions of adjacent tracks 28 and two brass connection terminals 35 which are connected to the tracks 28 on the tabs 16. Preferably the components 34,35 are soldered using a wave-soldering technique. Thermally conductive paste or pads may be placed between the LEDs 34 and the circuit board 32.
It will be noted from a study of Figures 1-5 that the circuit board 32 provides six parallel electrical sub-circuits between the terminals 35, each sub-circuit including a respective row of sixteen of the LEDs 34 daisy-chained in series and mounted on a respective one of the ribs 21. At this stage of the manufacture, the circuit board 32 may be tested by connecting an electrical supply to the terminals 35.
It will also be noted that the manufacture of the circuit board 32 50 far, including completion of the electrical circuitry, has been done on the flat, so that highly automated techniques can readily be employed.
For simplicity, in Figures 6-12 the heads and tails of the rivets 30 have not been shown.
Referring now to Figures 6-7, the circuit board 32 is then folded in a press between suitable dies along four parallel fold lines 36,38 at right-angles to the main slits 20. The fold lines 36 are at the ends of the slits 20, whereas the fold lines 38 are part way along the ribs 21 before the endmost LEDs 34 in the rows. During and after bending, the main portions 40 of the ribs 21 carrying the LEDs 34 remain planar. After bending, the two end portions 42 of the circuit board 32 beyond ends of the main slits 20 are coplanar in a plane parallel to the main portions 40 of the ribs 21. From a study of Figures 3A-B and 7, it will be noted that copper tracks 28 remain flat or are disposed on the insides of the folds so that the tracks 28 are not elongated during the bending process.
In the next step, a pair of formers 44 as shown in Figure 10 is employed. Each former 44 comprises a bar of hexagonal cross-section, where the length of side of the hexagon is slightly less than the width of each rib 21 of the circuit board 32. A diametric slot 46 is formed in one end of the former and has a width slightly larger than the thickness of the circuit board 32. The slots 46 are relieved (at 47) so as not to foul the terminals 35.
With the formers 44 coaxial and suitably spaced, the tabs 16 of the circuit board 32 are fitted into the slots 46 of the formers 44 and then folded, as shown in Figure 8, relative to the remainder of the circuit board 32 through an angle of 120 degrees along the line of the dashed slits 22 aligned with the edge 18 of the circuit board 32. These dashed slits 22 assist in producing a sharp fold. Then, the end portions 42 of the circuit board 32 are formed around the formers 44 with the end portions 42 creasing primarily along the other dashed slits 22, so that the end portions 42 form hexagonal sleeves 48 around the tabs 16. The formers are then withdrawn from the sleeves 42 leaving the circuit board 32 permanently deformed as shown in Figure 9.
It will seen from Figures 8 and 9 that, as the end portions 42 of the circuit board 32 are formed around the formers 44, the slits 20 open up and the main portions 40 of the six ribs 21 separate from one another leaving large gaps 49 between adjacent main portions 40. The circuit board 32 therefore forms an open skeleton on which the LEDs 34 and tracks 28 are mounted.
In an optional step, before or after the bending step, the circuit board 32 may be coated in an electrically-insulating lacquer after masking the light-emitting portions of the LEDs 34 and the connecting portions 35.
In order to complete the electric lamp 10, plastics material 50 is moulded around the sleeves 48, tabs 16 and inclined portions 52 of the ribs 21 and into a pair of end caps 54, while leaving the tips of the terminals 35 exposed, as shown in Figures 11-13. If desired, further plastics material 56 may be applied to the outwardly facing faces of the main portions 40 of the ribs 21 for example by moulding the material 56 directly onto the main portions 40 (provided that the light-emitting portions of the LEDs 34 are masked) or by moulding separate elements which are then attached to the main portions of the ribs 21. If such further plastics material 56 is employed, it preferably has high thermal conductivity and emissivity.
It will be appreciated that, when the electric lamp 10 is fitted to a complementary light fitting and electricity of the appropriate current and polarity is supplied via the terminals 35, the LEDs 34 will light up, the light radiation pattern of the whole electric lamp 10 depending, of course, on the light radiation pattern of each LED 34. As can be seen from Figure 12, the LEDs 34 are regularly arranged along the axis 60 of the lamp 10, with the optical axes 61 of the LEDs 34 at right angles to the lamp axis 60. Also, as can be seen from Figure 13, the LEDs 34 are regularly arranged around the axis 60 of the lamp 10, with the optical axes 61 of the LEDs 34 equiangularly spaced.
The LEDs 34 will generate heat, some of which will be conducted away by the main portions 40 of the ribs 21. The main portions 40 of the ribs 21 can then dissipate the heat to the ambient air, particularly from the inwardly-facing faces of the main portions 40. As can be seen particularly in Figure 13, the ambient air can freely travel through the gaps 49 between adjacent main portions 40 of the ribs 21 into and out of the space surrounded by the main portions 40 of theribs2l.
In the manufacture of the second embodiment of electric lamp 10 (Figures 20-21) emulating a conventional GLS bulb, a blank 12 (Figure 14) is employed, again comprising a flat sheet of aluminium having a thickness of, for example, 1 to 2 mm and to each face of which is bonded an electrically-insulating layer of polyethylene terephthalate film. The blank 12 is cut to have: a generally-rectangular rib-forming portion 13; a tip-forming portion 15 at one end of the rib-forming portion 13; a generally-rectangular sleeve-forming portion 17 at one end of the rib-forming portion 13; and a generally-rectangular tab 16 to one side of the sleeve-forming portion 17. The sleeve-forming portion 17 is equally subdivided by nine parallel dashed slits 22 into ten connected portions. A further dashed slit 23 is formed between the tab 16 and the sleeve-forming portion 17. The rib-forming portion 13 is also subdivided by nine continuous slits 20 into ten ribs 21. However, the slits 20 are not straight but instead deviate so that each rib 21 has a wider half 21w and a narrower half 21n, with the wider half 21w of each rib 21 being adjacent the narrower half or halves 21n of the adjacent rib(s). The edges of the blank 12 are shaped so that the outermost two ribs 21 have the same shape as the other eight ribs 21. The tip-forming portion 15 is notched along the end edge of the blank 12 so that a respective tapering tip 19 is provided for each rib 21. The roots of the notches stop short of the adjacent ends of the slits 20 so that the tips 19 are joined together.
Holes, as shown in Figure 1 for the first embodiment, are formed in the blank 12 at the locations of the required vias. The holes are lined with insulating sleeves as described above with reference to Figure 2. Copper tracks 28 are then placed on the blank 12 in the manner described above with reference to Figures 3A-B. Via rivets 30 are then fitted in the manner described above with reference to Figure 4. For reasons of simplicity, the copper tracks 28 and rivets 30 are shown only in Figures 14-15 of the drawings of the second embodiment. The copper tracks 28 on the reverse side of the blank 12 are shown in dashed lines.
Referring to Figure 15, the assembly of the circuit board 32 is completed by soldering a number of electrical components onto the blank 12. The components include ten rectangular surface-mount multi-junction LED chips 34 which are connected between portions of copper tracks on each of the wider halves 21w of the ribs 21, and one or more semiconductor chips 37 which are connected to copper pads on the tab 16. Other discrete components may also be fitted to the copper tracks. Thermally conductive paste or pads may be placed between the components 34,37 and the circuit board 32. The components 34,37 are preferably soldered using a wave-soldering technique. At this stage of the manufacture, the circuit board 32 may be tested by connecting an electrical supply to the terminal pads (not shown) on the tab 16.
The chips 37 may be arranged to control the current supplied to the LED chips 34 and to serve other functions. The copper tracks may connect the LED chips 34 to the chips 37 in any desired arrangement, for example driving all of the LED chips 34 in series with a single current controller, driving all of the LED chips 34 in parallel with a single current controller, or driving each LED chip 34 with its own respective current controller.
It will be noted that the manufacture of the circuit board 32 so far, including completion of the electrical circuitry, has been done on the flat, so that highly automated techniques can readily be employed.
Referring now to Figure 16, the circuit board 32 is then deformed in a press between suitable dies. The press creates a fold line 36 along the junction of the ribs 21 with the sleeve-forming portion 17. Also, the press deforms the narrower halves 21n of the ribs 21 into arcs, whereas the wider halves 21w of the ribs 21 remain planar. The tips 19 at the ends of the ribs 21 remain coplanar. The copper tracks and vias (not shown) on the circuit board 32 are arranged so that the copper tracks remain flat or are disposed on the insides of the folds or curves so that the tracks are not elongated during the bending process.
In the next step, a former 44 as shown in Figure 19 is employed. The former 44 comprises a bar of decagonal cross-section, where the length of side of the decagon is slightly less than the spacing of the dashed slits 22 of the circuit board 32. A diametric slot 46 is formed in one end of the former 44 and has a width slightly larger than the thickness of the circuit board 32. The slot 46 is relieved (at 47) so as not to foul the semiconductor chips 37.
The tab 16 of the circuit board 32 is fitted into the slot 46 of the former 44 and the tab 16 is then folded, as shown in Figure 17, relative to the remainder of the circuit board 32 through an angle of 108 degrees along the line of the dashed slits 23 between tab 16 and the sleeve-forming portion 17. These dashed slits 23 assist in producing a sharp fold. Then, the sleeve-forming portion 17 is formed around the former 44 with the sleeve forming portion 17 creasing primarily along the other dashed slits 22, so that the sleeve-forming portion 17 forms a decagonal sleeve 48 around the tab 16. The former 44 is then withdrawn from the sleeve 42 leaving the circuit board 32 permanently deformed as shown in Figure 18.
It will seen from Figures 17 and 18 that, as the sleeve-forming portion 42 of the circuit board 32 is formed around the former 44, the slits 20 between the ribs 21 open up leaving large gaps 49 between adjacent ribs 21 over most of their lengths. The circuit board 32 therefore forms an open skeleton on which the LED chips 34 and tracks are mounted. Furthermore, the notches between the tips 19 close up so that the tips 19 form a substantially continuous, generally frusto-conical surface.
In an optional step, before or after the bending steps, the circuit board 32 may be coated in an electrically-insulating lacquer after masking the light-emitting portions of the LED chips 34 and the pair of connecting pads (not shown) on the tab 16.
In order to complete the electric lamp 10, two terminals 35 are connected to the connecting pads on the tab 16, and then plastics material 50 is moulded around the sleeve 48 and tab 16 and into an end cap 54, while leaving the tips of the terminals 35 exposed, as shown in Figures 20-21. If desired, further plastics material may be applied to the outwardly facing faces of the ribs 21 for example by moulding the material directly onto the ribs 21 (provided that the light-emitting portions of the LED chips 34 are masked) or by moulding separate elements which are then attached to the ribs 21. If such further plastics material is employed, it preferably has high thermal conductivity and emissivity.
It will be appreciated that, when the electric lamp 10 is fitted to a complementary light fitting and electricity of the appropriate current and polarity is supplied via the terminals 35, the LEDs 34 will light up, the light radiation pattern of the whole electric lamp 10 depending, of course, on the light radiation pattern of each LED chips 34.
It should be noted, however, that the ten LED chips 34 are equiangularly spaced around the axis 60 of the lamp 10, with the five LED chips 34 further from the cap 54 having their optical axes 61a inclined at an angle of about 45 degrees to the lamp axis 60 in one direction, and with the other five LED chips 34 nearer to the cap 54 having their optical axes inclined at an angle of about 45 degrees in the opposite direction. Therefore, with an appropriate radiation pattern for the LED chips 34, an approximately uniform radiation pattern for the lamp 10 as a whole can be achieved over a radiation half-angle 62 (see Figure 21) of 150 degrees or more.
The LEDs 34 will generate heat, some of which will be conducted away by the ribs 21.
The ribs 21 can then dissipate the heat to the ambient air, particularly from the inwardly-facing faces of the ribs 21. As can be seen particularly in Figure 21, the ambient air can freely travel through the gaps 49 between adjacent ribs 21 into and out of the space surrounded by the ribs 21.
It will also be noted from Figure 21 that the ribs 21 and LED chips 34 lie within the envelope (as indicated by the dot-dash line 58) of a conventional GLS light bulb.
The manufacture of a third embodiment of electric lamp 10 emulating a GU1O spotlamp will now be described with reference to Figures 22 to 26. The manufacturing techniques are similar to those employed in the first and second embodiments, and the third embodiment will therefore be described only briefly.
A blank 12, as shown in Figure 22, of aluminium covered with insulating layers is cut and slit, and copper tracks and vias (not shown) are applied and formed as necessary. While the blank is still in the flat, six LEDs 34 and a control chip 37 are wave-soldered to the blank to form a circuit board 32 as shown in Figure 23. The circuit board 32 is then deformed as shown in Figure 24, with the portions of the circuit board 32 on which the LEDs 34 and chip 37 are mounted remaining flat. The circuit board 32 is then formed around a hexagonal former (not shown) to produce a sleeve 48, as shown in Figure 25, from which six ribs 21 radiate and then -10 -turn back on themselves to portions on which the LEDs 34 are mounted, the ribs 21 terminating in a short hexagonal collar 64. The optical axes 61 of the LEDs 34 converge to a point lying on the axis 60 of the sleeve 48. A pair of terminals 35 is connected to the circuit board 32. A plastics cap 54 is then moulded around the terminals 35 and sleeve 48 to form a lamp 10 as shown in Figure 26.
The manufacture of a fourth embodiment of electric lamp 10 emulating a conventional 12 V 21/5 W automotive brake-and tail-light bulb will now be described with reference to Figures 27-31. The manufacturing techniques are similar to those employed in the first and second embodiments, and the fourth embodiment will therefore be described only briefly.
A generally L-shaped blank 12 of aluminium, as shown in Figures 27A-B, is cut. One limb 66 of the L-shape is covered with insulating layers 68, as shown by cross-hatching, except for small regions 70 aligned on either side of the blank 12. The other limb 72 of the L-shape is not covered with insulating layers. Via holes 24,74 are formed in the blank 12. The via holes 24 are fitted with insulating sleeves (not shown), except for a hole 74 in the uninsulated regions 70.
Copper tracks 28 are formed on the blank 12 as shown in Figures 27A-B.
Via rivets 30,30A,82 are fitted to the holes 24, including an earthing via rivet 30A which is fitted to the hole 74 and connects its respective track to the aluminium of the blank 12.
Also, an electrically-insulating disc 76 with a pair of through holes is fitted to a tab portion 78 of the blank adjacent the root portion 80 of the L-shape and held in place by a pair of connecting rivets 82, as shown in Figures 28A-B. A single junction LED 34 and a current control chip 37 are placed on the blank 12, and the whole assembly is then wave soldered. The current control chip 37 and copper tracks 28 are configured so that: (a) when a supply voltage of about 12V is connected between one of the connecting rivets 30B and the aluminium of the blank 12, a relatively low constant current passes through the LED 34 so that is produces light of a similar brightness to a 5 W tungsten filament bulb; (b) when the supply voltage is connected between the other connecting rivet 30B and the aluminium of the blank 12, a higher constant current passes through the LED 34 so that is produces light of a similar brightness to a 21 W tungsten filament bulb; and (c) when the supply voltage is connected between both connecting rivets 30B and the aluminium of the blank 12, an even higher constant current passes through the LED 34 50 that is produces light of a similar brightness to both filaments of a 21/5 W tungsten filament bulb. The circuit board 32 may be tested at this stage.
The circuit board 32 is then permanently deformed as shown in Figures 29A-B. In particular, the tab portion 78 is bent fairly sharply through a right-angle relative to the root -11 -portion 80 in a first direction. The copper tracks 28 are on the inside of this bend so that they are not elongated by the bending process. The limb 66 is bent gently through an angle of about degrees relative to the root portion 80 in a second opposite direction. The copper tracks 28 are on the outside of this bend, but the bending is sufficiently gentle that the tracks are not elongated so greatly that they break. The limb 66 is also bent through an angle of about 110 degrees in the first direction to either side of the LED 34. The copper tracks 28 are on the inside of these bends so that they are not elongated by the bending process. The other limb 72 is also punched to form a pair of dimples 84 on one face of the limb 72 and protruding pins 86 on the other face of the limb 72 The bare aluminium limb 72 is then rolled into a cylindrical sleeve 48, as shown in Figures 30A-B, with the axis 60 of the sleeve 48 being coaxial with the LED 34 and the insulating disc 74. It will therefore be appreciated that the resulting lamp 10 can simply be arranged to emulate a conventional 12 V 21/5 W automotive brake-and tail-light bulb lying within the envelope (as indicated by the dot-dash line 58 in Figure 31) of a conventional BAY 15D light bulb.
It should be noted that the embodiments of the invention have been described above purely by way of example and that many modifications and developments may be made thereto within the scope of the present invention.

Claims (17)

  1. -12 -CLAIMS1. An electric lamp comprising: a plurality of electrically-powered light sources; at least one electrical connector electrically connected to the light sources; and a structure to which the light sources are mounted with different orientations and to which the connector(s) is/are mounted; wherein: the structure has the form of an open, three-dimensional skeleton of members so that ambient air can circulate through the skeleton and around the members; the light sources are mounted in thermal contact with the members; and the members are thermally conductive so that they can dissipate heat away from the light sources.
  2. 2. A lamp as claimed in claim 1, wherein: the skeleton is substantially rigid.
  3. 3. A lamp as claimed in claim 1 or 2, wherein: at least some of the members of the skeleton are formed of metal.
  4. 4. A lamp as claimed in any preceding claim, wherein: at least some of the members of the skeleton are integrally formed.
  5. 5. A lamp as claimed in claim 4, wherein: at least some of the members of the skeleton are integrally formed from an initially flat piece of material.
  6. 6. A lamp as claimed in any preceding claim, wherein: at least some of the members of the skeleton carry electrically-conductive tracks connecting at least in part the light sources to the electrical connector(s).
    -13 -
  7. 7. A lamp as claimed in any preceding claim, wherein: the light sources are substantially rigidly mounted on the members.
  8. 8. A lamp as claimed in any preceding claim, wherein: the lamp has an axis; and the light sources are substantially regularly arranged around the axis.
  9. 9. A lamp as claimed in any preceding claim, wherein: each light source has an optical axis.
  10. 10. A lamp as claimed in claim 9, wherein: the optical axes of all or at least one group of the light sources extend substantially at right angles to the axis of the lamp.
  11. 11. A lamp as claimed in claim 9 or 10, wherein: the optical axes of all or at least a first group of the light sources lie substantially on a first common cone.
  12. 12. A lamp as claimed in claim 11, wherein: the axis of the first common cone is substantially coaxial with the axis of the lamp.
  13. 13. A lamp as claimed in claim 11 or 12, wherein: the optical axes of a second group of the light sources lie substantially on a second common cone substantially coaxial with the first common cone.
  14. 14. A lamp as claimed in any preceding claim, wherein: the light sources are LEDs.
  15. 15. A lamp as claimed in any preceding claim, wherein: the lamp is devoid of an enclosure enveloping the skeleton and the light sources.
  16. 16. An electric lamp substantially as described with reference to the drawings.-14 -
  17. 17. An electric lamp as claimed in any preceding claim in combination with a lamp fitting, wherein: the lamp fitting has at least one electrical connector engaging the electrical connector(s) of lamp; and the lamp fitting is devoid of an enclosure enveloping the skeleton and the light sources of the lamp.
GB1020452.7A 2010-12-03 2010-12-03 Electric lamp Withdrawn GB2483942A (en)

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GB2483942A true GB2483942A (en) 2012-03-28

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WO2014031567A1 (en) * 2012-08-22 2014-02-27 Metrospec Technology, L.L.C. Led lighting systems and methods
US9341355B2 (en) 2008-03-06 2016-05-17 Metrospec Technology, L.L.C. Layered structure for use with high power light emitting diode systems
US9357639B2 (en) 2008-03-18 2016-05-31 Metrospec Technology, L.L.C. Circuit board having a plated through hole through a conductive pad
US9736946B2 (en) 2008-02-14 2017-08-15 Metrospec Technology, L.L.C. Flexible circuit board interconnection and methods
US10334735B2 (en) 2008-02-14 2019-06-25 Metrospec Technology, L.L.C. LED lighting systems and methods
US10849200B2 (en) 2018-09-28 2020-11-24 Metrospec Technology, L.L.C. Solid state lighting circuit with current bias and method of controlling thereof
US11266014B2 (en) 2008-02-14 2022-03-01 Metrospec Technology, L.L.C. LED lighting systems and method

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US20040037079A1 (en) * 2002-08-26 2004-02-26 Luk John F. Flexible LED lighting strip
US20080062687A1 (en) * 2006-05-09 2008-03-13 Herman Miller, Inc. Lamp
US20090147511A1 (en) * 2007-10-25 2009-06-11 Simon Jerome H Lumenairs Having Structurally and Electrically Integrated Arrangements of Quasi Point Light Sources, Such as LEDS
WO2009115063A1 (en) * 2008-03-17 2009-09-24 Osram Gesellschaft mit beschränkter Haftung Arrangement, lamp arrangement and method for emitting light

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US20040037079A1 (en) * 2002-08-26 2004-02-26 Luk John F. Flexible LED lighting strip
US20080062687A1 (en) * 2006-05-09 2008-03-13 Herman Miller, Inc. Lamp
US20090147511A1 (en) * 2007-10-25 2009-06-11 Simon Jerome H Lumenairs Having Structurally and Electrically Integrated Arrangements of Quasi Point Light Sources, Such as LEDS
WO2009115063A1 (en) * 2008-03-17 2009-09-24 Osram Gesellschaft mit beschränkter Haftung Arrangement, lamp arrangement and method for emitting light

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9736946B2 (en) 2008-02-14 2017-08-15 Metrospec Technology, L.L.C. Flexible circuit board interconnection and methods
US10334735B2 (en) 2008-02-14 2019-06-25 Metrospec Technology, L.L.C. LED lighting systems and methods
US10499511B2 (en) 2008-02-14 2019-12-03 Metrospec Technology, L.L.C. Flexible circuit board interconnection and methods
US11266014B2 (en) 2008-02-14 2022-03-01 Metrospec Technology, L.L.C. LED lighting systems and method
US11304308B2 (en) 2008-02-14 2022-04-12 Metrospec Technology, L.L.C. Flexible circuit board interconnection and methods
US11690172B2 (en) 2008-02-14 2023-06-27 Metrospec Technology, L.L.C. LED lighting systems and methods
US9341355B2 (en) 2008-03-06 2016-05-17 Metrospec Technology, L.L.C. Layered structure for use with high power light emitting diode systems
US9357639B2 (en) 2008-03-18 2016-05-31 Metrospec Technology, L.L.C. Circuit board having a plated through hole through a conductive pad
WO2014031567A1 (en) * 2012-08-22 2014-02-27 Metrospec Technology, L.L.C. Led lighting systems and methods
US10849200B2 (en) 2018-09-28 2020-11-24 Metrospec Technology, L.L.C. Solid state lighting circuit with current bias and method of controlling thereof

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