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WO1996013048A1 - Electric lamp - Google Patents

Electric lamp Download PDF

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Publication number
WO1996013048A1
WO1996013048A1 PCT/IB1995/000800 IB9500800W WO9613048A1 WO 1996013048 A1 WO1996013048 A1 WO 1996013048A1 IB 9500800 W IB9500800 W IB 9500800W WO 9613048 A1 WO9613048 A1 WO 9613048A1
Authority
WO
WIPO (PCT)
Prior art keywords
heat
conducting
housing
ballast means
lamp
Prior art date
Application number
PCT/IB1995/000800
Other languages
French (fr)
Inventor
Cornelis Johannes Mies
Theodoor Hubert Stommen
Original Assignee
Philips Electronics N.V.
Philips Norden Ab
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 Philips Electronics N.V., Philips Norden Ab filed Critical Philips Electronics N.V.
Publication of WO1996013048A1 publication Critical patent/WO1996013048A1/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/52—Cooling arrangements; Heating arrangements; Means for circulating gas or vapour within the discharge space
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/30—Vessels; Containers
    • H01J61/32—Special longitudinal shape, e.g. for advertising purposes
    • H01J61/327—"Compact"-lamps, i.e. lamps having a folded discharge path
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/56—One or more circuit elements structurally associated with the lamp

Definitions

  • the invention relates to an electric lamp comprising a light source provided with a vessel which is closed in a gastight manner and transmits radiation, a housing connected to the light source and provided with a lamp cap, - ballast means electrically connected to the light source for operating the light source and positioned at least partly in a space surrounded by the housing, a heat-conducting body which is in contact with a portion of the ballast means and with the housing.
  • Such an electric lamp is known from US Patent 4,739,222.
  • the known lamp is a compact fluorescent lamp designed for replacing an incandescent lamp in general lighting applications.
  • a major advantage of compact fluorescent lamps over incandescent lamps is their much higher luminous efficacy.
  • a disadvantage of many compact fluorescent lamps is that the lamp dimensions are comparatively great, whereby the practical application possibilities are strongly reduced.
  • Many manufacturers of compact fluorescent lamps have sought possibilities for reducing the dimensions of these lamps in order to counteract this disadvantage.
  • a major problem in such a size reduction is the heat balance: in proportion as the ballast means are placed closer to the light source and closer to one another, the temperature of these ballast means during stationary lamp operation will rise. This rise in temperature usually adversely affects the life of some components forming part of the ballast means.
  • a method of improving the heat transfer from the ballast means via the housing to the surroundings is to encapsulate the ballast means in the housing by means of a synthetic resin. Once the synthetic resin has set, it forms a heat-conducting connection between components forming part of the ballast means and the housing. A satisfactory cooling of the ballast means during lamp operation is realised by means of these conductive connections. At the same time, however, the weight of the lamp increases, and encapsulation is a problematic process step in the manufacture of the lamp.
  • ballast means In the electric lamp known from US Patent 4,739,222, cooling of a component forming part of the ballast means is realised in that a heat-conducting body is provided which is in contact with the component and with the housing. The relevant component is effectively cooled during lamp operation by this measure. If the ballast means comprise a number of components, however, which must all be cooled during lamp operation because otherwise the temperature of these components would reach too high a value, it is necessary to connect each of these components to the housing by means of a heat-conducting body. The manufacturing process of the lamp becomes comparatively complicated in this latter case, and the lamp becomes comparatively expensive.
  • the invention has for its object inter alia to provide an electric lamp which is comparatively simple to manufacture and whose ballast means are effectively cooled during lamp operation also with comparatively small lamp dimensions.
  • ballast means comprise a heat-conducting plate on which at least some of the components of the remaining ballast means are provided, and in that the heat-conducting body forms part of a heat-conducting connection between the housing and the heat-conducting plate.
  • the material from which the plate is manufactured preferably has a heat conduction coefficient of at least 20 W/mK (wau7metres*Kelvin). Mounting of those components which generate a comparatively great quantity of heat during lamp operation on the heat-conducting plate achieves that these components are all cooled via only one heat- conducting body and the heat-conducting plate.
  • the heat-conducting connection between the housing and the heat-conducting plate may be formed in that the heat-conducting body is so positioned that it is in contact with one of the components placed on the heat-conducting plate and with the housing.
  • the heat-conducting body preferably comprises a heat-conducting paste. Since the paste is plastically deformable, it is very simple to position the heat-conducting body during the manufacturing process of the electric lamp in such a way that there is a good contact with the housing and with the ballast means. Also, no mechanical forces are exerted on the ballast means when a plastically deformable heat-conducting body is used, in contrast to the situation in which an elastically deformable heat-conducting body is used.
  • the material from which the heat-conducting plate is formed may be chosen to be, for example, a metal whose surface is coated with a synthetic-resin or enamel layer for realising electrical insulation of the components placed on the plate.
  • a simpler solution, however, is to form the heat-conducting plate fiom one material which has a high heat conduction coefficient and which is also electrically insulating.
  • An effective cooling of the ballast means can be achieved when the heat-conducting plate comprises a material chosen from the group formed by Al 2 O 3 , AIN, and BeO.
  • the heat conduction coefficients of these materials are 20-35, 110-170, and 150-250 W/mK.
  • ballast means comprise a hybrid circuit provided on the heat- conducting plate.
  • a hybrid circuit is here understood to mean a circuit partly comprising discrete components and partly comprising components provided by silk-screen printing techniques on the surface of the heat-conducting plate. The use of a hybrid circuit renders it possible to make some of the ballast means comparatively small, so that the electric lamp can be comparatively small. Thanks to the presence of the heat-conducting plate and the heat- conducting body, these comparatively small ballast means are also effectively cooled dunng lamp operation.
  • Fig. 1 shows an embodiment of part of an electric lamp according to the invention in side elevation and partly in cross-section.
  • a light source 8 is provided with a (discharge) vessel which is closed in a gastight manner and transmits radiation.
  • a housing 6 is connected to the light source and provided with a lamp cap 3, in this embodiment that part of the housing which is below the broken line A.
  • This housing may be formed, for example, from a synthetic resin.
  • B are ballast means electrically connected to the light source. This connection is indicated with broken lines 9 in Fig. 1.
  • the ballast means B are placed in a space 7 which is surrounded by the housing 6.
  • a heat-conducting plate P forms part of the ballast means B.
  • the heat-conducting plate P is fastened in the space 7 by means not shown in Fig. 1.
  • the ballast means further comprise components mounted on the heat-conducting plate and diagrammatically shown in Fig. 1 as C1-C4.
  • D is a quantity of heat-conducting paste which forms a heat-conducting body which is contact with both the housing and the heat-conducting plate P.
  • E forms current-conducting connections between the ballast means B and metal contacts 1 and 2 placed on the lamp cap, a supply voltage being present between said contacts during lamp operation.
  • the operation of the electric lamp shown in Fig. 1 is as follows.
  • the ballast means When a supply voltage is present between the metal contacts 1 and 2, the ballast means generate a current which flows through the discharge vessel forming part of the light source 8 via the connection 9. As a result, the light source radiates light.
  • the components of the ballast means are heated by the electric currents which flow through the ballast means during lamp operation.
  • the components are also heated by heat transported from the light source to the ballast means through conduction, radiation, and convection.
  • the heat-conducting plate P forms a heat-conducting interconnection between the components provided on the heat-conducting plate.
  • the housing 6 serves as a heat sink because the heat-conducting plate is connected with heat conduction to the housing 6 through the heat-conducting body D so that the ballast means are effectively cooled through the heat conduction plate P, the heat-conducting body D, and the housing 6.
  • the heat-conducting plate P was made of Al 2 O 3 in an electric lamp having a power rating of 11 W and constructed as the embodiment shown in Fig. 1. The dimensions of the plate were 1.3 cm x 2.7 cm x 0.65 mm.
  • the heat-conducting body D was formed from approximately 0.5 g of a heat-conducting paste: Eccotherm TC-4 from Grace Electronic Material.
  • the lamp housing was formed from polycarbonate. The temperature of a switching element forming part of the ballast means was found to be approximately 5-10° C lower during stationary lamp operation than in a corresponding lamp in which the heat- conducting body was absent.
  • the plate P was formed from a material with a heat conduction coefficient below 0.5 W/mK, all dimensions remaining the same, it was found that the temperature of the switching element was more than 40° C higher than in the electric lamp according to the invention during stationary lamp operation.

Landscapes

  • Arrangement Of Elements, Cooling, Sealing, Or The Like Of Lighting Devices (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

The invention relates to an electric lamp comprising a light source provided with a vessel which is closed in a gastight manner and transmits radiation, a housing connected to the light source and provided with a lamp cap, ballast means electrically connected to the light source for operating the light source and positioned at least partly in a space surrounded by the housing, a heat-conducting body which is in contact with a portion of the ballast means and with the housing. According to the invention, the lamp is also provided with a heat-conducting plate on which at least some of the components of the remaining ballast means are provided. The heat-conducting body also forms part of a heat-conducting connection between the housing and the heat-conducting plate. An effective cooling of the ballast means is achieved thereby during lamp operation.

Description

Electric lamp.
The invention relates to an electric lamp comprising a light source provided with a vessel which is closed in a gastight manner and transmits radiation, a housing connected to the light source and provided with a lamp cap, - ballast means electrically connected to the light source for operating the light source and positioned at least partly in a space surrounded by the housing, a heat-conducting body which is in contact with a portion of the ballast means and with the housing.
Such an electric lamp is known from US Patent 4,739,222. The known lamp is a compact fluorescent lamp designed for replacing an incandescent lamp in general lighting applications. A major advantage of compact fluorescent lamps over incandescent lamps is their much higher luminous efficacy. A disadvantage of many compact fluorescent lamps is that the lamp dimensions are comparatively great, whereby the practical application possibilities are strongly reduced. Many manufacturers of compact fluorescent lamps have sought possibilities for reducing the dimensions of these lamps in order to counteract this disadvantage. A major problem in such a size reduction is the heat balance: in proportion as the ballast means are placed closer to the light source and closer to one another, the temperature of these ballast means during stationary lamp operation will rise. This rise in temperature usually adversely affects the life of some components forming part of the ballast means. A method of improving the heat transfer from the ballast means via the housing to the surroundings is to encapsulate the ballast means in the housing by means of a synthetic resin. Once the synthetic resin has set, it forms a heat-conducting connection between components forming part of the ballast means and the housing. A satisfactory cooling of the ballast means during lamp operation is realised by means of these conductive connections. At the same time, however, the weight of the lamp increases, and encapsulation is a problematic process step in the manufacture of the lamp.
In the electric lamp known from US Patent 4,739,222, cooling of a component forming part of the ballast means is realised in that a heat-conducting body is provided which is in contact with the component and with the housing. The relevant component is effectively cooled during lamp operation by this measure. If the ballast means comprise a number of components, however, which must all be cooled during lamp operation because otherwise the temperature of these components would reach too high a value, it is necessary to connect each of these components to the housing by means of a heat-conducting body. The manufacturing process of the lamp becomes comparatively complicated in this latter case, and the lamp becomes comparatively expensive.
The invention has for its object inter alia to provide an electric lamp which is comparatively simple to manufacture and whose ballast means are effectively cooled during lamp operation also with comparatively small lamp dimensions.
According to the invention, this object is achieved in that the ballast means comprise a heat-conducting plate on which at least some of the components of the remaining ballast means are provided, and in that the heat-conducting body forms part of a heat-conducting connection between the housing and the heat-conducting plate.
The material from which the plate is manufactured preferably has a heat conduction coefficient of at least 20 W/mK (wau7metres*Kelvin). Mounting of those components which generate a comparatively great quantity of heat during lamp operation on the heat-conducting plate achieves that these components are all cooled via only one heat- conducting body and the heat-conducting plate. The heat-conducting connection between the housing and the heat-conducting plate may be formed in that the heat-conducting body is so positioned that it is in contact with one of the components placed on the heat-conducting plate and with the housing. It is more advantageous, however, to place the heat-conducting body in such a way that it is in contact both with the heat-conducting plate and with the housing, so that the heat removed through the heat-conducting connection during lamp operation does not flow entirely through one of the components but through the heat-conducting plate.
The heat-conducting body preferably comprises a heat-conducting paste. Since the paste is plastically deformable, it is very simple to position the heat-conducting body during the manufacturing process of the electric lamp in such a way that there is a good contact with the housing and with the ballast means. Also, no mechanical forces are exerted on the ballast means when a plastically deformable heat-conducting body is used, in contrast to the situation in which an elastically deformable heat-conducting body is used.
The material from which the heat-conducting plate is formed may be chosen to be, for example, a metal whose surface is coated with a synthetic-resin or enamel layer for realising electrical insulation of the components placed on the plate. A simpler solution, however, is to form the heat-conducting plate fiom one material which has a high heat conduction coefficient and which is also electrically insulating. An effective cooling of the ballast means can be achieved when the heat-conducting plate comprises a material chosen from the group formed by Al2O3, AIN, and BeO. The heat conduction coefficients of these materials are 20-35, 110-170, and 150-250 W/mK.
A favourable embodiment of an electric lamp according to the invention is characterized in that the ballast means comprise a hybrid circuit provided on the heat- conducting plate. A hybrid circuit is here understood to mean a circuit partly comprising discrete components and partly comprising components provided by silk-screen printing techniques on the surface of the heat-conducting plate. The use of a hybrid circuit renders it possible to make some of the ballast means comparatively small, so that the electric lamp can be comparatively small. Thanks to the presence of the heat-conducting plate and the heat- conducting body, these comparatively small ballast means are also effectively cooled dunng lamp operation.
Embodiments of the invention will be explained with reference to a drawing.
In the drawing, Fig. 1 shows an embodiment of part of an electric lamp according to the invention in side elevation and partly in cross-section.
In Fig. 1 , a light source 8 is provided with a (discharge) vessel which is closed in a gastight manner and transmits radiation. A housing 6 is connected to the light source and provided with a lamp cap 3, in this embodiment that part of the housing which is below the broken line A. This housing may be formed, for example, from a synthetic resin. B are ballast means electrically connected to the light source. This connection is indicated with broken lines 9 in Fig. 1. The ballast means B are placed in a space 7 which is surrounded by the housing 6. A heat-conducting plate P forms part of the ballast means B. The heat-conducting plate P is fastened in the space 7 by means not shown in Fig. 1. The ballast means further comprise components mounted on the heat-conducting plate and diagrammatically shown in Fig. 1 as C1-C4. D is a quantity of heat-conducting paste which forms a heat-conducting body which is contact with both the housing and the heat-conducting plate P. E forms current-conducting connections between the ballast means B and metal contacts 1 and 2 placed on the lamp cap, a supply voltage being present between said contacts during lamp operation.
The operation of the electric lamp shown in Fig. 1 is as follows. When a supply voltage is present between the metal contacts 1 and 2, the ballast means generate a current which flows through the discharge vessel forming part of the light source 8 via the connection 9. As a result, the light source radiates light. The components of the ballast means are heated by the electric currents which flow through the ballast means during lamp operation. The components are also heated by heat transported from the light source to the ballast means through conduction, radiation, and convection. The heat-conducting plate P, however, forms a heat-conducting interconnection between the components provided on the heat-conducting plate. The housing 6 serves as a heat sink because the heat-conducting plate is connected with heat conduction to the housing 6 through the heat-conducting body D so that the ballast means are effectively cooled through the heat conduction plate P, the heat-conducting body D, and the housing 6.
The heat-conducting plate P was made of Al2O3 in an electric lamp having a power rating of 11 W and constructed as the embodiment shown in Fig. 1. The dimensions of the plate were 1.3 cm x 2.7 cm x 0.65 mm. The heat-conducting body D was formed from approximately 0.5 g of a heat-conducting paste: Eccotherm TC-4 from Grace Electronic Material. The lamp housing was formed from polycarbonate. The temperature of a switching element forming part of the ballast means was found to be approximately 5-10° C lower during stationary lamp operation than in a corresponding lamp in which the heat- conducting body was absent. If not only the heat-conducting body was absent, but also the plate P was formed from a material with a heat conduction coefficient below 0.5 W/mK, all dimensions remaining the same, it was found that the temperature of the switching element was more than 40° C higher than in the electric lamp according to the invention during stationary lamp operation.

Claims

CLAIMS;
1 • An electric lamp comprising a light source provided with a vessel which is closed in a gastight manner and transmits radiation, a housing connected to the light source and provided with a lamp cap, - ballast means electrically connected to the light source for operating the light source and positioned at least partly in a space surrounded by the housing, a heat-conducting body which is in contact with a portion of the ballast means and with the housing, characterized in that the ballast means comprise a heat-conducting plate on which at least some of the components of the remaining ballast means are provided, and in that the heat- conducting body forms part of a heat-conducting connection between the housing and the heat-conducting plate.
2. An electric lamp as claimed in Claim 1, wherein the heat conduction coefficient of the material from which the heat-conducting plate is formed is at least 20 W/mK.
3. An electric lamp as claimed in Claim 1 or 2, wherein the heat-conducting body is in contact with the heat-conducting plate and with the housing.
4. An electric lamp as claimed in any or several of the preceding Claims, wherein the heat-conducung body is formed from a heat-conducting paste.
5. An electric lamp as claimed in any one or several of the preceding
Claims, wherein the heat-conducting plate comprises a material chosen from the group formed by Al2O3, AIN, and BeO.
6. An electric lamp as claimed in any one or several of the preceding
Claims, wherein the ballast means comprise a hybrid circuit provided on the heat-conducting plate.
PCT/IB1995/000800 1994-10-19 1995-09-26 Electric lamp WO1996013048A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP94203039.6 1994-10-19
EP94203039 1994-10-19

Publications (1)

Publication Number Publication Date
WO1996013048A1 true WO1996013048A1 (en) 1996-05-02

Family

ID=8217294

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB1995/000800 WO1996013048A1 (en) 1994-10-19 1995-09-26 Electric lamp

Country Status (1)

Country Link
WO (1) WO1996013048A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1139388A1 (en) 2000-03-27 2001-10-04 Matsushita Electronics Corporation Bulb-form lamp and manufacturing method of lamp case
EP1248283A1 (en) * 2001-04-04 2002-10-09 E. Energy Technology Ltd. Novel structures for electronically-controlled compact fluorescent lamps
US6794801B2 (en) * 2001-10-31 2004-09-21 Toshiba Lighting & Technology Corporation Compact selfballasted fluorescent lamp and luminaire
WO2006053687A2 (en) * 2004-11-16 2006-05-26 Patent-Treuhand- Gesellschaft Für Elektrische Glühlampen Mbh Lamp base assembly with electronic ballast for energy-saving lamp
US7224125B2 (en) 2002-10-04 2007-05-29 International Rectifier Corporation Dimmable fluorescent lamp package
WO2009142909A2 (en) * 2008-05-23 2009-11-26 Osram Sylvania, Inc. Integrated ceramic metal halide high frequency ballast assembly

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4389595A (en) * 1979-09-29 1983-06-21 Tokyo Shibaura Denki Kabushiki Kaisha Fluorescent lamp
EP0136454A1 (en) * 1983-08-30 1985-04-10 Bodenseewerk Gerätetechnik GmbH Device for the heat dissipation of printed circuit boards
US4739222A (en) * 1985-05-07 1988-04-19 Hitachi, Ltd. Compact fluorescent lamp with a screw base

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4389595A (en) * 1979-09-29 1983-06-21 Tokyo Shibaura Denki Kabushiki Kaisha Fluorescent lamp
EP0136454A1 (en) * 1983-08-30 1985-04-10 Bodenseewerk Gerätetechnik GmbH Device for the heat dissipation of printed circuit boards
US4739222A (en) * 1985-05-07 1988-04-19 Hitachi, Ltd. Compact fluorescent lamp with a screw base

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1139388A1 (en) 2000-03-27 2001-10-04 Matsushita Electronics Corporation Bulb-form lamp and manufacturing method of lamp case
US6734633B2 (en) 2000-03-27 2004-05-11 Matsushita Electronics Corporation Bulb-form lamp and manufacturing method of lamp case
EP1248283A1 (en) * 2001-04-04 2002-10-09 E. Energy Technology Ltd. Novel structures for electronically-controlled compact fluorescent lamps
US6794801B2 (en) * 2001-10-31 2004-09-21 Toshiba Lighting & Technology Corporation Compact selfballasted fluorescent lamp and luminaire
US7224125B2 (en) 2002-10-04 2007-05-29 International Rectifier Corporation Dimmable fluorescent lamp package
US7633230B2 (en) 2002-10-04 2009-12-15 International Rectifier Corporation Dimmable fluorescent lamp package
WO2006053687A2 (en) * 2004-11-16 2006-05-26 Patent-Treuhand- Gesellschaft Für Elektrische Glühlampen Mbh Lamp base assembly with electronic ballast for energy-saving lamp
WO2006053687A3 (en) * 2004-11-16 2006-10-19 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Lamp base assembly with electronic ballast for energy-saving lamp
US7755265B2 (en) 2004-11-16 2010-07-13 Osram Gesellschaft Mit Beschraenkter Haftung Lamp base assembly with electronic ballast for energy-saving lamp
WO2009142909A2 (en) * 2008-05-23 2009-11-26 Osram Sylvania, Inc. Integrated ceramic metal halide high frequency ballast assembly
WO2009142909A3 (en) * 2008-05-23 2010-06-03 Osram Sylvania, Inc. Integrated ceramic metal halide high frequency ballast assembly
CN102037540A (en) * 2008-05-23 2011-04-27 奥斯兰姆施尔凡尼亚公司 Integrated ceramic metal halide high frequency ballast assembly

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