WO2008142630A1 - Lampe à décharge et phares pour véhicule motorisé - Google Patents

Lampe à décharge et phares pour véhicule motorisé Download PDF

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Publication number
WO2008142630A1
WO2008142630A1 PCT/IB2008/051952 IB2008051952W WO2008142630A1 WO 2008142630 A1 WO2008142630 A1 WO 2008142630A1 IB 2008051952 W IB2008051952 W IB 2008051952W WO 2008142630 A1 WO2008142630 A1 WO 2008142630A1
Authority
WO
WIPO (PCT)
Prior art keywords
discharge
lamp
discharge vessel
electrodes
reflector
Prior art date
Application number
PCT/IB2008/051952
Other languages
English (en)
Inventor
Lukas Kuepper
Norbert Lesch
Albrecht Kraus
Original Assignee
Philips Intellectual Property & Standards Gmbh
Koninklijke Philips Electronics N. V.
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 Intellectual Property & Standards Gmbh, Koninklijke Philips Electronics N. V. filed Critical Philips Intellectual Property & Standards Gmbh
Publication of WO2008142630A1 publication Critical patent/WO2008142630A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields
    • H01J61/06—Main electrodes
    • H01J61/073—Main electrodes for high-pressure discharge lamps
    • H01J61/0732—Main electrodes for high-pressure discharge lamps characterised by the construction of the electrode

Definitions

  • the invention relates to a discharge lamp with asymmetric brightness distribution, comprising a discharge vessel for generating an electric discharge, in which discharge vessel two electrodes connected with current conductors are accommodated in a gastight manner.
  • the invention further relates to an automotive headlight comprising a reflector and a discharge lamp with asymmetric brightness distribution arranged in the reflector.
  • a discharge lamp generally comprises a cap, a burner with a discharge vessel and an outer bulb.
  • the cap serves to hold the burner in place and to position and electrically contact the lamp in a headlight.
  • the actual light generation takes place in the discharge vessel.
  • the discharge vessel is generally surrounded by an outer bulb of glass. This outer bulb serves to filter UV radiation from the emitted light.
  • bi-projection optical systems cannot provide optimum illumination due to the different brightness distribution as compared to mercury-containing xenon lamps.
  • the development of optimized bi-projection optical systems especially for mercury- free xenon lamps is very costly, particularly also when the increasing demand for miniaturization of automotive components is taken into account.
  • An automotive headlight comprises a reflector and a lamp projecting through an aperture into the interior of the reflector.
  • the lamp and the associated cap are accurately positioned in a holder of the reflector, so that the discharge vessel is arranged in an exactly known location.
  • the emitted light illuminates the reflector surface.
  • a headlight beam is thus formed which emits in the forward direction.
  • dipped beam headlights must exhibit for instance an asymmetric light distribution with, basically, a horizontally clearly defined bright-dark boundary so as to preclude dazzling of oncoming traffic.
  • the illumination at point 75 R being the relevant measuring point for the range of the headlight, must be at least 12 lux. Only half a degree away from this measuring point, the bright-dark boundary runs, across which there is the so-termed zone III of glare in which the illumination must not exceed 0.7 lux.
  • Most headlights are comprised of so-termed projection optical systems including an elliptic mirror which focuses the light originating from the light source on a diaphragm forming the bright-dark boundary line, and of a lens which images the light distribution thus formed into the space reserved for traffic.
  • a good headlight is characterized by the highest possible contrast in the area of the bright-dark boundary.
  • a higher contrast is achieved, on the one hand, by a high as possible luminance value and, on the other hand, by an accurately defined position of the light arc in the headlight. Therefore, an ideal light source would be punctiform.
  • Conventional automotive gas discharge lamps have a specified axial and lateral dimension of the light arc, with the position of the arc center being accurately defined.
  • the brightness distribution of the arc around this accurately defined position should be as symmetric as possible, since each deviation from a symmetric distribution leads to a more or less pronounced deviation of the headlight beam from the desired light distribution.
  • a discharge lamp having an asymmetric brightness distribution is desirable, which lamp enables accurate focusing within the headlamp reflector and, in addition, fulfills the minimum requirements regarding the illumination on the system of coordinates of the European measuring screen.
  • DE 35 19 627 Al discloses a discharge lamp in which the electrodes have a different temperature gradient during operation of the lamp in order to exhibit an asymmetric brightness distribution of the discharge arc.
  • the electrode having the higher light emission at the desired location within the headlight reflector and to direct the light emitted from this location with the highest possible, desired light intensity according to the European measuring screen.
  • the colder, darker electrode is arranged at a location in the reflector which contributes less to the illumination of the irradiated surface.
  • the ideal of a punctiform light source is approximated, resulting in a substantial improvement of the quality of the surface to be illuminated relative to the automotive headlights used hitherto.
  • the invention wants to provide a remedy. It is an object of the invention to provide a discharge lamp having an asymmetric brightness distribution, which lamp is both easy and economical to manufacture and does not have the above-mentioned drawbacks. In accordance with the invention, this object is achieved in that the electrodes are of similar construction and project over a different distance into the discharge vessel.
  • the invention provides a discharge lamp having an asymmetric brightness distribution, which discharge lamp is easy and economical to manufacture and does not have the above-mentioned drawbacks.
  • the known manufacturing methods can still be used as before because electrodes having a small diameter are still being employed.
  • the difference in temperature gradient is achieved in that the electrodes extend over a different length into the discharge vessel.
  • the discharge vessel is provided with a reflective coating. This has a further influence on the heat distribution.
  • infrared-reflecting layers are capable of reflecting infrared radiation back in the direction of the electrodes, as a result of which the electrode temperature can be further increased.
  • the discharge lamp is embodied so as to be free of mercury. Consequently, requirements regarding the environment are taken into account.
  • this object is achieved by using a discharge lamp in accordance with the invention having an asymmetric brightness distribution.
  • the invention provides an automotive headlight which provides improved illumination while simultaneously fulfilling the requirements of the European measuring screen.
  • Fig. 1 is a diagrammatic view of a discharge lamp having asymetric brightness distribution and
  • Fig. 2 is a diagrammatic view of a bi-projection optical system.
  • the discharge lamp 10 selected as an exemplary embodiment comprises a cap 12, a burner 14 with a discharge vessel 16 and leads 18.
  • Said leads 18 accommodate electric conductors which are connected with electrodes 22 in the inner volume of the discharge vessel 16 via sealing foils 23.
  • the discharge vessel 16 is sealed at opposite ends by means of a pinch 17.
  • the outer current supply leads 18 are electrically connected, in known manner using sealing foils 23, with the electrodes 22 arranged inside the discharge vessel 16.
  • a voltage to the leads 18, which are connected with the electrodes 22 in said manner By applying a voltage to the leads 18, which are connected with the electrodes 22 in said manner, a gas discharge can be generated in the interior of the discharge vessel 16.
  • Such discharge lamps are known in a plurality of variations to the person skilled in the art, so that the known construction and functioning do not have to be discussed in more detail herein.
  • the electrodes 22 are introduced into the discharge vessel 16 so as to extend over a different length relative to one another.
  • the electrode 22a close to the cap projects approximately 2 mm into the discharge vessel 16; the oppositely arranged electrode 22b projects only 1.9 mm into the discharge vessel 16.
  • the spacing between the electrodes is approximately 4 mm.
  • the discharge vessel 16 is provided at specific parts of its surface with a coating that absorbs visible radiation.
  • Fig. 2 is a longitudinal cross-sectional view of an embodiment of a headlight 30.
  • the headlight 30 comprises a reflector 32 as well as the lamp 10 shown in the figure above, which lamp projects into the interior of the reflector housing through a central aperture of the reflector 32, so that the discharge vessel 16 is centrally arranged at a predetermined location inside the reflector housing.
  • the cap 12 is accommodated in a holder, not shown in detail, of the reflector housing. From there, electrical contact is made with the lamp 10.
  • the projection optical system 40 comprises an elliptic mirror 42, a movable diaphragm 44, a projection lens 46 as well as a lamp 10 which projects into the bi- projection optical system (Fig. 2) through a central aperture of the elliptic mirror 42.
  • the lamp 10 is centrally positioned inside the reflector housing.
  • the cap 12 is accommodated in a holder (not shown in detail) of the reflector housing.
  • the light source Q (in this example represented by the light arc formed between the electrodes 22 in the discharge vessel 16) is imaged via the elliptic mirror 42 in the plane of the movable diaphragm 44 and from there, via the projection lens 46, into the traffic space V.
  • the projection from the diaphragm edge constitutes the bright-dark boundary HD and separates the illuminated part of the traffic space from the non-illuminated part of the traffic space.
  • the brightness distribution in the area of the electrode 22a close to the cap is very important.
  • the beam path of the electrode 22a close to the cap is shown as an uninterrupted line in Fig. 2, whereas the beam path of the electrode 22b remote from the cap is shown as an interrupted line in Fig. 2).
  • Differently formed diaphragm edges enable headlight beams to be adjusted for different traffic situations.

Landscapes

  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

L'invention concerne une lampe à décharge à distribution de luminosité asymétrique comprenant un récipient de décharge (16) pour générer une décharge électrique, dans lequel deux électrodes (22a, 22b) connectées à des conducteurs de courant sont disposées de manière étanche aux gaz, lesdites électrodes (22a, 22b) étant de conception identique et s'étendant sur une distance différente dans le récipient de décharge (16). L'invention concerne également un phare d'automobile comprenant un réflecteur et une lampe à décharge (10) à distribution de luminosité asymétrique disposée dans ledit réflecteur.
PCT/IB2008/051952 2007-05-24 2008-05-19 Lampe à décharge et phares pour véhicule motorisé WO2008142630A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP07108794.4 2007-05-24
EP07108794 2007-05-24

Publications (1)

Publication Number Publication Date
WO2008142630A1 true WO2008142630A1 (fr) 2008-11-27

Family

ID=39739429

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2008/051952 WO2008142630A1 (fr) 2007-05-24 2008-05-19 Lampe à décharge et phares pour véhicule motorisé

Country Status (1)

Country Link
WO (1) WO2008142630A1 (fr)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4161672A (en) * 1977-07-05 1979-07-17 General Electric Company High pressure metal vapor discharge lamps of improved efficacy
DE3519627A1 (de) * 1985-05-31 1986-12-04 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 8000 München Hochdruckentladungslampe zur verwendung in kraftfahrzeugscheinwerfern
US4724361A (en) * 1984-12-14 1988-02-09 Matsushita Electric Works, Ltd. High pressure discharge lamp
US5258691A (en) * 1990-11-14 1993-11-02 General Electric Company Metal halide lamp having improved operation acoustic frequencies
US6246170B1 (en) * 1997-11-18 2001-06-12 Canon Kabushiki Kaisha Light source apparatus with a spherical optical member
US6359376B1 (en) * 1998-09-18 2002-03-19 Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen Mbh Fluorescent lamp having asymmetric electrodes inside the discharge tube
WO2003060946A2 (fr) * 2002-01-16 2003-07-24 Koninklijke Philips Electronics N.V. Lampe a decharge de gaz
WO2005038858A2 (fr) * 2003-10-17 2005-04-28 Philips Intellectual Property & Standards Gmbh Bruleur aux halogenures a fentes reduites au minimum pourvu d'une chambre a decharge en ceramique

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4161672A (en) * 1977-07-05 1979-07-17 General Electric Company High pressure metal vapor discharge lamps of improved efficacy
US4724361A (en) * 1984-12-14 1988-02-09 Matsushita Electric Works, Ltd. High pressure discharge lamp
DE3519627A1 (de) * 1985-05-31 1986-12-04 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 8000 München Hochdruckentladungslampe zur verwendung in kraftfahrzeugscheinwerfern
US5258691A (en) * 1990-11-14 1993-11-02 General Electric Company Metal halide lamp having improved operation acoustic frequencies
US6246170B1 (en) * 1997-11-18 2001-06-12 Canon Kabushiki Kaisha Light source apparatus with a spherical optical member
US6359376B1 (en) * 1998-09-18 2002-03-19 Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen Mbh Fluorescent lamp having asymmetric electrodes inside the discharge tube
WO2003060946A2 (fr) * 2002-01-16 2003-07-24 Koninklijke Philips Electronics N.V. Lampe a decharge de gaz
WO2005038858A2 (fr) * 2003-10-17 2005-04-28 Philips Intellectual Property & Standards Gmbh Bruleur aux halogenures a fentes reduites au minimum pourvu d'une chambre a decharge en ceramique

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