WO2013009724A2 - Led bulb with overlapping shell to compensate for thermal expansion - Google Patents

Led bulb with overlapping shell to compensate for thermal expansion Download PDF

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Publication number
WO2013009724A2
WO2013009724A2 PCT/US2012/046000 US2012046000W WO2013009724A2 WO 2013009724 A2 WO2013009724 A2 WO 2013009724A2 US 2012046000 W US2012046000 W US 2012046000W WO 2013009724 A2 WO2013009724 A2 WO 2013009724A2
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WO
WIPO (PCT)
Prior art keywords
shell
led light
light bulb
fill material
pieces
Prior art date
Application number
PCT/US2012/046000
Other languages
French (fr)
Other versions
WO2013009724A3 (en
Inventor
Carol Lenk
Ronald Lenk
Original Assignee
Reliabulb, Llc
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 Reliabulb, Llc filed Critical Reliabulb, Llc
Publication of WO2013009724A2 publication Critical patent/WO2013009724A2/en
Publication of WO2013009724A3 publication Critical patent/WO2013009724A3/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V3/00—Globes; Bowls; Cover glasses
    • F21V3/02—Globes; Bowls; Cover glasses characterised by the shape
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/20—Light sources comprising attachment means
    • F21K9/23—Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
    • F21K9/232—Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/50—Cooling arrangements
    • F21V29/502—Cooling arrangements characterised by the adaptation for cooling of specific components
    • F21V29/506—Cooling arrangements characterised by the adaptation for cooling of specific components of globes, bowls or cover glasses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • the present invention relates to compensating for volumetric expansion in a light- emitting diode (LED) light bulb, and more particularly, to using an overlapping shell design to accomplish this compensation in the construction of LED light bulbs.
  • LED light- emitting diode
  • LEDs are highly energy-efficient light sources, which may make LEDs more desirable than other light sources, for example incandescent or fluorescent lighting.
  • light emitted by LEDs tends to be fairly directional, that is, the emitted light tends to be projected primarily along a forward axis, which is typically an
  • the fill material can partially or wholly remedy the directionality of the light emitted from the LEDs by scattering the light into a more uniform pattern.
  • the fill material can reduce the thermal resistance from the LEDs to the ambient, helping to reduce the temperature of the LEDs.
  • gel has been suggested for the fill material. A gel can be made that disperses light, and has a certain degree of thermal conductivity.
  • a thermally conductive material such as a silicone putty can be used between an LED heatsink and the LED light bulb shell.
  • the fill material very frequently has a coefficient of thermal expansion different from that of the LED light bulb shell into which it is placed. If the fill material has a coefficient of thermal expansion that is sufficiently greater than that of the LED light bulb shell, as the temperature of the LED light bulb increases the fill material could potentially burst the shell. Conversely, if the fill material has a coefficient of thermal expansion that is sufficiently less than that of the LED light bulb shell, as the temperature of the LED light bulb increases, the fill material could pull away from the shell, significantly increasing the thermal resistance from the LEDs to the ambient.
  • the present disclosure is directed to LED light bulbs that compensate for differences in thermal expansion in the components of the LED light bulb.
  • the invention provides for a shell constructed from two or more sections.
  • the sections are constructed to partially overlap each other.
  • the shell expands at the seam or seams between the sections, ensuring that the shell is not subjected to undue pressure due to thermal expansion, while not necessarily exposing the inside of the bulb to the external environment.
  • one or more of the fill materials adhere to the material of the shell.
  • the shell contracts at the seam or seams between the sections, ensuring that the shell remains in thermal contact with the one or more fill materials.
  • the contraction causes the overlap between the sections to increase.
  • the shell expands at the seam or seams between the sections, ensuring that the shell is not subjected to undue pressure.
  • the shell is in two pieces exhibiting rotational symmetry around the axis of symmetry of the LED light bulb.
  • the overlap of the two pieces is in a plane including the axis of symmetry of the LED light bulb.
  • the shell overlap may only partially compensate for the differential between thermal expansion of the one or more fill materials compared to that of the shell material.
  • the one or more fill materials may be sufficiently rigid that the fill materials do not flow.
  • the shell expansion may pull the shell sections apart, ensuring that the shell is not subjected to undue pressure.
  • the one or more fill materials are exposed to the environment in the narrow region that is no longer covered by the shell. In one embodiment, one or more of the fill materials adhere to the material of the shell.
  • the shell contracts at the seam or seams between the sections, which may cause the shell sections to overlap, ensuring that the shell remains in thermal contact with the one or more fill materials.
  • FIG. 1 is a drawing of an LED light bulb according to one or more embodiments shown and described herein.
  • FIG. 2 is a drawing of an LED light bulb in which the fill material has thermally expanded more than the shell according to one or more embodiments shown and described herein.
  • FIG. 3 is a drawing of an LED light bulb in which the fill material has thermally expanded less than the shell according to one or more embodiments shown and described herein.
  • FIG. 4 is a drawing of an LED light bulb in which the fill material has thermally expanded more than the shell, with the shell partially separated at its seam
  • FIG. 5 is a drawing of an LED light bulb in which the fill material is a thermal interface between a heatsink and the shell.
  • FIG. 1 is a drawing of an LED light bulb 10, with a shell 20 consisting of two sections 21 and 22.
  • the sections 21 and 22 are shown with rotational symmetry around the axis of symmetry 23 of the bulb 10, although other or additional symmetries are also contemplated.
  • the two sections 21 and 22 have a small overlap region 30.
  • FIG. 2 is a drawing of a two-section shell LED light bulb 10, in which the fill material 40 has thermally expanded more than the shell 20, with the shell 20 still covering the fill material 40.
  • the greater thermal expansion of the fill material 40 as compared to the shell 20 may be due to an increase in temperature of the fill material 40 as compared to the shell 20, an increased coefficient of thermal expansion of the fill material 40 as compared to the shell 20, or a combination thereof.
  • the fill material 40 tends to push the two sections 21 and 22 of the shell 20 apart.
  • the overlap region 30 of the two sections 21 and 22 of the shell 20 has decreased in size from 31 to 32, as compared with FIG. 1 .
  • FIG. 3 is a drawing of a two-section shell LED light bulb 10, in which the fill material 40 has thermally expanded less than the shell 20, with the shell 20 pulled in by the fill material 40.
  • the greater thermal expansion of the shell 20 as compared to the fill material 40 may be due to an increased coefficient of thermal expansion of the shell 20 as compared to the fill material 40.
  • the fill material 40 pulls the two sections 21 and 22 of the shell 20 together. As illustrated in FIG. 3, the overlap region 30 of the two sections 21 and 22 of the shell 20 has increased in size from 31 to 33, as compared with FIG. 1 .
  • FIG. 4 is a drawing of an LED light bulb 10, in which the fill material 40 has thermally expanded more than the shell 20, with the shell 20 partially separated at its seam 50.
  • the fill material 40 has pushed the two sections 21 and 22 of the shell 20 completely apart. There is no longer an overlap region 30 of the two sections 21 and 22 of the shell 20.
  • the fill material 40 is now slightly exposed in the seam 50 to the environment outside of the shell 20.
  • FIG. 5 is a drawing of an LED light bulb 10 in which the fill material 40 is a thermal interface material between a heatsink 60 and the shell 20.
  • the two sections 21 and 22 of the shell 20 can move apart or together as necessary to ensure a continuous good thermal path from the heatsink 60 to the shell 20.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Optics & Photonics (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
  • Led Device Packages (AREA)

Abstract

Compensation for volumetric expansion in a light-emitting diode (LED) light bulb, and more particularly, the use of an overlapping shell design to accomplish this compensation in the construction of LED light bulbs.

Description

LED BULB WITH OVERLAPPING SHELL TO COMPENSATE FOR THERMAL
EXPANSION
The present invention relates to compensating for volumetric expansion in a light- emitting diode (LED) light bulb, and more particularly, to using an overlapping shell design to accomplish this compensation in the construction of LED light bulbs.
LEDs are highly energy-efficient light sources, which may make LEDs more desirable than other light sources, for example incandescent or fluorescent lighting. However, light emitted by LEDs tends to be fairly directional, that is, the emitted light tends to be projected primarily along a forward axis, which is typically an
axisymmetric axis of the LED light bulb. Off the forward axis, light intensity from the LEDs drops off, often fairly dramatically. Additionally, LEDs dissipate significant power in regions local to the diodes themselves. The individual diodes' ability to withstand high temperatures is limited. To dissipate heat away from the individual diodes, heat dissipation features, for example, large heatsinks or fans, have been integrated into LED light bulbs to attempt to keep the diodes adequately cooled. These heat dissipation features may not be aesthetically pleasing and may potentially compromise the appearance of the LED light bulb.
One of the methods that has been attempted to resolve these issues has been to fill the LED light bulb with some substance that either scatters the light, conducts heat away from the LEDs, or both. By scattering the light, the fill material can partially or wholly remedy the directionality of the light emitted from the LEDs by scattering the light into a more uniform pattern. By conducting heat away from the LEDs, the fill material can reduce the thermal resistance from the LEDs to the ambient, helping to reduce the temperature of the LEDs. In one particular instantiation, gel has been suggested for the fill material. A gel can be made that disperses light, and has a certain degree of thermal conductivity. In another particular instantiation, a thermally conductive material such as a silicone putty can be used between an LED heatsink and the LED light bulb shell. Until now, such filled LED light bulbs have had a number of significant problems. One of these is that the fill material very frequently has a coefficient of thermal expansion different from that of the LED light bulb shell into which it is placed. If the fill material has a coefficient of thermal expansion that is sufficiently greater than that of the LED light bulb shell, as the temperature of the LED light bulb increases the fill material could potentially burst the shell. Conversely, if the fill material has a coefficient of thermal expansion that is sufficiently less than that of the LED light bulb shell, as the temperature of the LED light bulb increases, the fill material could pull away from the shell, significantly increasing the thermal resistance from the LEDs to the ambient.
Further, in practical cases, there are often multiple different materials inside or attached to the LED light bulb shell, each with its own unique coefficient of thermal expansion. For example, there may be a metallic heatsink, and the fill material must interface between this heatsink and the shell. For a further example, there may be multiple different materials comprising the fill material at differing positions inside the LED light bulb shell. These possibilities compound the problems of mismatched coefficients of thermal expansion, and may again result in bursting or pull-away.
The present disclosure is directed to LED light bulbs that compensate for differences in thermal expansion in the components of the LED light bulb.
The invention provides for a shell constructed from two or more sections. The sections are constructed to partially overlap each other. When one or more of the fill materials inside the shell thermally expands more than the shell material does, the shell expands at the seam or seams between the sections, ensuring that the shell is not subjected to undue pressure due to thermal expansion, while not necessarily exposing the inside of the bulb to the external environment. In one embodiment, one or more of the fill materials adhere to the material of the shell. Then, when one or more of the fill materials thermally contracts more than the shell material does, the shell contracts at the seam or seams between the sections, ensuring that the shell remains in thermal contact with the one or more fill materials. The contraction causes the overlap between the sections to increase. When one or more of the fill materials expands more than the shell material does, the shell expands at the seam or seams between the sections, ensuring that the shell is not subjected to undue pressure.
In one embodiment, the shell is in two pieces exhibiting rotational symmetry around the axis of symmetry of the LED light bulb. The overlap of the two pieces is in a plane including the axis of symmetry of the LED light bulb.
In a further embodiment, the shell overlap may only partially compensate for the differential between thermal expansion of the one or more fill materials compared to that of the shell material. The one or more fill materials may be sufficiently rigid that the fill materials do not flow. When the one or more fill materials expands due to an elevated temperature more than the shell material expands, the shell expansion may pull the shell sections apart, ensuring that the shell is not subjected to undue pressure. The one or more fill materials are exposed to the environment in the narrow region that is no longer covered by the shell. In one embodiment, one or more of the fill materials adhere to the material of the shell. When one or more of the fill materials thermally contracts more than the shell material does, the shell contracts at the seam or seams between the sections, which may cause the shell sections to overlap, ensuring that the shell remains in thermal contact with the one or more fill materials. The accompanying drawing is included to provide a further understanding of the invention, and is incorporated in and constitute a part of this specification. The drawing illustrates an embodiment of the invention and, together with the description, serves to explain the principles of the invention.
FIG. 1 is a drawing of an LED light bulb according to one or more embodiments shown and described herein.
FIG. 2 is a drawing of an LED light bulb in which the fill material has thermally expanded more than the shell according to one or more embodiments shown and described herein.
FIG. 3 is a drawing of an LED light bulb in which the fill material has thermally expanded less than the shell according to one or more embodiments shown and described herein.
FIG. 4 is a drawing of an LED light bulb in which the fill material has thermally expanded more than the shell, with the shell partially separated at its seam
according to one or more embodiments shown and described herein.
FIG. 5 is a drawing of an LED light bulb in which the fill material is a thermal interface between a heatsink and the shell.
Reference will now be made in detail to one or more embodiments of the present disclosure, which is illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawing and the description to refer to the same or like parts. FIG. 1 is a drawing of an LED light bulb 10, with a shell 20 consisting of two sections 21 and 22. The sections 21 and 22 are shown with rotational symmetry around the axis of symmetry 23 of the bulb 10, although other or additional symmetries are also contemplated. As shown in FIG. 1 , the two sections 21 and 22 have a small overlap region 30.
FIG. 2 is a drawing of a two-section shell LED light bulb 10, in which the fill material 40 has thermally expanded more than the shell 20, with the shell 20 still covering the fill material 40. The greater thermal expansion of the fill material 40 as compared to the shell 20 may be due to an increase in temperature of the fill material 40 as compared to the shell 20, an increased coefficient of thermal expansion of the fill material 40 as compared to the shell 20, or a combination thereof. As the fill material 40 increases in temperature, the fill material 40 tends to push the two sections 21 and 22 of the shell 20 apart. As illustrated in FIG. 2, the overlap region 30 of the two sections 21 and 22 of the shell 20 has decreased in size from 31 to 32, as compared with FIG. 1 .
FIG. 3 is a drawing of a two-section shell LED light bulb 10, in which the fill material 40 has thermally expanded less than the shell 20, with the shell 20 pulled in by the fill material 40. The greater thermal expansion of the shell 20 as compared to the fill material 40 may be due to an increased coefficient of thermal expansion of the shell 20 as compared to the fill material 40. The fill material 40 pulls the two sections 21 and 22 of the shell 20 together. As illustrated in FIG. 3, the overlap region 30 of the two sections 21 and 22 of the shell 20 has increased in size from 31 to 33, as compared with FIG. 1 .
FIG. 4 is a drawing of an LED light bulb 10, in which the fill material 40 has thermally expanded more than the shell 20, with the shell 20 partially separated at its seam 50. The fill material 40 has pushed the two sections 21 and 22 of the shell 20 completely apart. There is no longer an overlap region 30 of the two sections 21 and 22 of the shell 20. The fill material 40 is now slightly exposed in the seam 50 to the environment outside of the shell 20.
FIG. 5 is a drawing of an LED light bulb 10 in which the fill material 40 is a thermal interface material between a heatsink 60 and the shell 20. The two sections 21 and 22 of the shell 20 can move apart or together as necessary to ensure a continuous good thermal path from the heatsink 60 to the shell 20.
It will be apparent to those skilled in the art that various modifications and variation can be made to the structure of the present disclosure without departing from the scope or spirit of the embodiments disclosed herein. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of the embodiments provided they fall within the scope of the following claims and their equivalents.

Claims

1 . An LED light bulb comprising:
a plurality of pieces of a shell; and
at least one fill material inside the shell;
wherein at least one of the plurality of pieces of the shell are capable of motion at least partially independently of the others.
2. The LED light bulb of claim 1 , wherein said plurality of pieces of the shell is aligned with a symmetry axis of said LED light bulb.
3. The LED light bulb of claim 1 , wherein said plurality of pieces of the shell is separable to accommodate expansion of said at least one fill material.
4. The LED light bulb of claim 1 , wherein a first of said plurality of pieces of the shell overlaps a second of said plurality of pieces of the shell.
5. The LED light bulb of claim 4, wherein said first of said plurality of pieces of the shell continues to at least partially overlap said second of said plurality of pieces of the shell when said at least one fill material expands.
6. The LED light bulb of claim 4, wherein said first of said plurality of pieces of the shell no longer overlaps said second of said plurality of pieces of the shell when said at least one fill material expands.
7. The LED light bulb of claim 1 , wherein said at least one fill material adheres to said shell pieces.
8. The LED light bulb of claim 1 , wherein a first of said at least one fill material has a coefficient of thermal expansion different than a coefficient of thermal expansion of a second of said at least one fill material.
9. The LED light bulb of claim 1 , wherein at least one of said fill materials provides a thermal interface between a heatsink and at least one of said plurality of pieces of the shell.
PCT/US2012/046000 2011-07-11 2012-07-10 Led bulb with overlapping shell to compensate for thermal expansion WO2013009724A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201161506237P 2011-07-11 2011-07-11
US61/506,237 2011-07-11

Publications (2)

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WO2013009724A2 true WO2013009724A2 (en) 2013-01-17
WO2013009724A3 WO2013009724A3 (en) 2013-03-28

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105179974A (en) * 2015-10-12 2015-12-23 上海昭关照明实业有限公司 LED lamp

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003049971A1 (en) * 2001-11-16 2003-06-19 Tufte Brian N Lighting apparatus
US20090045933A1 (en) * 2007-08-17 2009-02-19 Whelen Engineering Company, Inc. LED Warning Light
US20090309473A1 (en) * 2006-05-02 2009-12-17 Superbulbs, Inc. Heat removal design for led bulbs
US20100164346A1 (en) * 2008-12-31 2010-07-01 Intematix Corporation Light emitting device with phosphor wavelength conversion
US7828453B2 (en) * 2009-03-10 2010-11-09 Nepes Led Corporation Light emitting device and lamp-cover structure containing luminescent material

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003049971A1 (en) * 2001-11-16 2003-06-19 Tufte Brian N Lighting apparatus
US20090309473A1 (en) * 2006-05-02 2009-12-17 Superbulbs, Inc. Heat removal design for led bulbs
US20090045933A1 (en) * 2007-08-17 2009-02-19 Whelen Engineering Company, Inc. LED Warning Light
US20100164346A1 (en) * 2008-12-31 2010-07-01 Intematix Corporation Light emitting device with phosphor wavelength conversion
US7828453B2 (en) * 2009-03-10 2010-11-09 Nepes Led Corporation Light emitting device and lamp-cover structure containing luminescent material

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105179974A (en) * 2015-10-12 2015-12-23 上海昭关照明实业有限公司 LED lamp

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