EP0501668A2 - Source lumineuse à réflecteur ellipsoidal perfectionné - Google Patents

Source lumineuse à réflecteur ellipsoidal perfectionné Download PDF

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Publication number
EP0501668A2
EP0501668A2 EP92301360A EP92301360A EP0501668A2 EP 0501668 A2 EP0501668 A2 EP 0501668A2 EP 92301360 A EP92301360 A EP 92301360A EP 92301360 A EP92301360 A EP 92301360A EP 0501668 A2 EP0501668 A2 EP 0501668A2
Authority
EP
European Patent Office
Prior art keywords
light source
reflector
disposed
metal halide
arc tube
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Withdrawn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
EP92301360A
Other languages
German (de)
English (en)
Other versions
EP0501668A3 (en
Inventor
John Martin Davenport
William Walter Finch
Richard Lowell Hansler
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.)
General Electric Co
Original Assignee
General Electric Co
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 General Electric Co filed Critical General Electric Co
Publication of EP0501668A2 publication Critical patent/EP0501668A2/fr
Publication of EP0501668A3 publication Critical patent/EP0501668A3/en
Withdrawn legal-status Critical Current

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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
    • F21V7/00—Reflectors for light sources
    • F21V7/0025—Combination of two or more reflectors for a single light source
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/20—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by refractors, transparent cover plates, light guides or filters
    • F21S41/24—Light guides
    • 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
    • F21V7/00—Reflectors for light sources
    • F21V7/0008—Reflectors for light sources providing for indirect lighting

Definitions

  • This invention relates to an improved design for a light source using an ellipsoidal reflector. More particularly, this invention relates to such a light source as utilizes a gas discharge type of light source such as a metal halide arc tube, in conjunction with an ellipsoidal reflector and efficient optical fiber coupling of the light source output to a remote position.
  • a gas discharge type of light source such as a metal halide arc tube
  • a gas discharge light source such as a metal halide arc tube
  • a metal halide arc tube in conjunction with a parabolic reflector for each of the forward lighting positions, which it is understood can be as many as four, has proven advantageous over the previously utilized incandescent type of lighting arrangement because of the above-listed gas discharge source characteristics.
  • the metal halide arc tube has been a part of the overall design effort directed at reducing the dimensions and numbers of components at the forward end of the vehicle. It has been well recognized and documented that if designers could reduce the profile of the vehicle front end, the effect would be to improve the aerodynamic performance and hence fuel efficiency of such vehicle.
  • optical fibers provide an efficient means for transmitting light from one location to another.
  • the goal in coupling such fiber optics to the light source is to find the most efficient arrangement that results in the least amount of light lost between the light source output and the entry point of the grouping of optical fibers that will then be distributed throughout the vehicle.
  • a known method of efficiently coupling the light source to the fiber optics is to provide an ellipsoidal reflector with the light source placed at one focus and the fiber optics placed at the other.
  • Still another approach is to provide a collimating lens arrangement which focuses the light output from the source such that it can be more efficiently gathered at the entry point of the bundle of fiber optic cables.
  • an improved light source and coupling arrangement which utilizes a metal halide arc tube energized by means of a DC voltage as the source of light.
  • the metal halide arc tube is disposed in a vertical manner within an ellipsoidal reflector such that the anode connection to the arc tube is disposed at the bottom of the arc tube as opposed to the topmost disposed cathode connection.
  • the arc tube is disposed within the reflector in a manner which is offset from the optical focal point of the reflector. In this manner, the portion of the vertically oriented metal halide arc tube in which the molten liquid halide collects, does not interfere with the reflective properties of the light source within the ellipsoidal reflector.
  • the improved light source and optical coupling arrangement may further contain a mirrored element to reflect light into the bundle of optical fibers. Additionally, the improved light source and optical coupling arrangement may provide for a thermal isolation between the ballast used to drive the light source and the light source/coupling arrangement.
  • Figure 1 is an elevational view partly in block diagram form of an improved light source and optical coupling arrangement constructed in accordance with the present invention.
  • Figure 2 is an elevational view partly in section detailing the light source and reflector portion of the present invention.
  • an improved light source and optical coupling arrangement 10 constructed in accordance with the present invention, includes a first segment 12 which contains the lighting and optics components, and a second segment 14 which contains the voltage supply circuitry for energizing the lighting components.
  • the output of the first segment 12 is illustrated as including a number of optical fibers 16 which extend to the various lighting positions associated with the vehicle (not shown).
  • U.S. Patent No. 4,904,907 issued to Allison et al. and assigned to the same assignee as the present invention is referred to and is hereby incorporated by reference.
  • the circuitry which comprises the ballast electronics of the second segment 14 is disposed within a separate container 18 which provides thermal isolation of the electronics contained therein from any heat generated by the components disposed in the first segment 12.
  • the output of the ballast circuit of second segment 12 is coupled to a lamp device disposed within a reflector element 20, such lamp device to be described hereinafter in further detail.
  • the reflector device 20 shown as part of the first segment 12, is an ellipsoidal reflector oriented in a downward facing direction with respect to the actual orientation of the light output from the second segment 12 which is channelled to the appropriate lighting positions in a horizontal orientation.
  • the output of the ellipsoidal reflector 20 is directed to the surface of a mirror element 22 which is oriented at approximately a 45 degree angle such that the transposition of the downward directed light output to a horizontal plane is achieved.
  • the mirror element 22 can be a cold mirror; that is, the portions of the light output from the lamp that would result in the generation of heat would be removed by means of a filter arrangement.
  • the mirror element 22 may be coated with multiple layers of a dielectric coating to reduce the amount of infrared and ultraviolet light incident on an optical coupling shown in fig. 1 in block diagram form as reference 24.
  • the inner surface of reflector element 20 can be similarly coated for the same purpose.
  • a hot mirror could be used in conjunction with the cold mirror without departing from the scope of the present invention.
  • the optical coupling device 24 shown in fig. 1 performs the function of gathering at the input ends of the optical fibers 16, the highest percentage of input light as possible.
  • the optical coupling can be affected merely by positioning the input ends (not shown) of the optical fibers at the focussed light spot shown here as reference (a) and occurring at the righthandmost side of the optical coupling device 24.
  • the optical coupling in its simplest form merely involves positioning of the optical fiber input ends at the light focus point (a), however, it is contemplated that the present invention encompasses additional coupling arrangements as for instance, a collimating lens arrangement instead of the mirror element 22 disclosed herein.
  • optical fibers are intended to include an optical light guide which may have a larger diameter than a fiber and/or may be hollow in construction.
  • the first segment 12 includes a housing 26 in which the lighting and optical components are disposed in thermal separation from the ballast electronics of the second segment 14. It is also possible to dispose both the first and second segments 12 and 14 in a common housing to preserve space. In this approach, the thermal separation between the two segments could be achieved by means of a metal or thermal partition between the segments that would prevent the heat generated by the lighting devices from adversely affecting the electronics of the second segment 14.
  • the optimization of the light output for the first segment 12 is achieved by placement of the lamp 28 within the reflector 20 as shown in fig. 2.
  • the lamp 28 is a metal halide arc tube vertically disposed within the downward facing reflector 20.
  • this invention is primarily directed to an automotive lighting application, which because such application relies on a DC source of energy, typically results in the metal halide lamp 28 having an anode electrode 30 disposed in the bottom end of a lamp envelope 34 and a cathode electrode 32, disposed at the upper end of the lamp envelope 34. It should be understood however that the DC output of the automotive battery could be modulated so that it would be possible to utilize a lamp operable by means of an AC source.
  • the anode electrode 30 is disposed in the lower position to balance the otherwise asymmetric heating caused by the natural convection currents within the lamp. Since more heat must be dissipated by the hotter running anode electrode 30, for a lamp operating from a DC source, by disposing the anode electrode 30 in the lower position, a more symmetric balance of convection heating can be achieved than would otherwise be available. In operating a low wattage metal halide arc tube, which in this instance can be on the order of 35 watts, it is necessary to consider the effects of cataphoresis.
  • metal halide ions are influenced by the electric fields caused by either a DC power source or by a low frequency AC source such that the ions are driven towards one or both of the ends of the lamp envelope. It can be appreciated that under such an influence, these driven halides would not contribute to the amount of halides occurring between the electrodes and therefore, do not contribute to the desired illumination.
  • the metal halide lamp 28 is constructed having the anode electrode 30 of a substantially greater thickness than that of the cathode electrode 32.
  • the cathode electrode 32 constructed of approximately 9 mil tungsten rod whereas the anode electrode 30 would be constructed of approximately 40 mil bullet shaped tungsten rod.
  • an additional molybdenum outer lead 36 is disposed on the cathode end of the lamp envelope 34. Additionally, the end of the lamp envelope 34 in which the cathode electrode 32 is disposed is longer than the end for the anode electrode 30.
  • the elongated portion 34a of the lamp envelope 34 serves the purpose of providing means for securing the metal halide lamp 28 at the optimum position within the reflector 20 as will hereinafter be discussed.
  • Electrical connectors 38 and 40 provide the source of energy for the metal halide lamp 28 in a conventional manner.
  • lamp 28 can contain 1.9 mg of 19:1 molar ratio of sodium scandium iodide as well as 1.4 mg of Mercury and six atmospheres of Xenon. Additionally, metal halide lamp 28 can be constructed with an arc gap of 2.4 mm. With the addition of the multiple atmospheres of Xenon, light will be produced in an essentially instantaneous manner when a high current is passed through the discharge during starting.
  • the metal halide lamp 28 within the ellipsoidal reflector 20 is proposed.
  • the vertically oriented metal halide lamp 28 can be disposed within the downward facing ellipsoidal reflector 20 such that light collected by the ellipsoidal reflector 20 will come through only the upper portion of the metal halide lamp 28 which is free from molten metal halide. If the metal halide lamp 28 is operated vertically, the molten metal halide will tend to be restricted to no more than the lower 1/3 of the lamp envelope 34.
  • the desired effect of avoiding light passing through the molten metal halide can be achieved by positioning the metal halide lamp 28 within the ellipsoidal reflector 20 in a manner offset from the first optical focal point of the reflector 20. Since the molten metal halide will reside in approximately the lower 1/3 of the metal halide lamp 28, positioning of the lamp 28 should be such that only the upper 2/3 of the metal halide lamp 28 is located at the first optical focal point of the ellipsoidal reflector 20. In other words, the arc is central at the first focal point and moved down until only light passing through the upper 2/3 of the bulb is intercepted by the ellipsoidal reflector.
  • the metal halide lamp 28 will be secured in the ellipsoidal reflector 20 such that there can be no deviation from such position.
  • One way of securing the metal halide lamp 28 in the reflector 20 is by the use of a cement (not shown).
  • the cement can be placed in the neck portion 20a of the ellipsoidal reflector 20 and allowed to first air dry for a short period of time. Following this air drying step, the cement can be heated for another period of time, which initial heating can be provided merely by operating the metal halide lamp 28. Finally, the cement can be further cured by a short period of high temperature firing (approx.400 degrees C).

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
  • Fastening Of Light Sources Or Lamp Holders (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
EP19920301360 1991-02-25 1992-02-19 Improved light source design using ellipsoidal reflector Withdrawn EP0501668A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US660388 1984-10-12
US66038891A 1991-02-25 1991-02-25

Publications (2)

Publication Number Publication Date
EP0501668A2 true EP0501668A2 (fr) 1992-09-02
EP0501668A3 EP0501668A3 (en) 1993-03-17

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920301360 Withdrawn EP0501668A3 (en) 1991-02-25 1992-02-19 Improved light source design using ellipsoidal reflector

Country Status (2)

Country Link
EP (1) EP0501668A3 (fr)
JP (1) JPH0582100A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5530940A (en) * 1995-02-02 1996-06-25 Rohm And Haas Company Coupling device for light pipe system
US6220740B1 (en) * 1993-10-20 2001-04-24 General Electric Company High efficiency dual output light source

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5122913B2 (ja) * 2007-10-26 2013-01-16 パナソニック株式会社 照明器具
JP5966843B2 (ja) 2012-10-18 2016-08-10 ソニー株式会社 光源装置及び画像表示装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0219137A2 (fr) * 1985-10-18 1987-04-22 Kabushiki Kaisha Toshiba Phare pour véhicule
US4811172A (en) * 1987-11-23 1989-03-07 General Electric Company Lighting systems employing optical fibers

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH065614B2 (ja) * 1985-04-08 1994-01-19 東芝ライテック株式会社 反射形メタルハライドランプ

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0219137A2 (fr) * 1985-10-18 1987-04-22 Kabushiki Kaisha Toshiba Phare pour véhicule
US4811172A (en) * 1987-11-23 1989-03-07 General Electric Company Lighting systems employing optical fibers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
NTIS TECHNICAL NOTES vol. B, no. 3, March 1986, SPRINGFIELD VIRGINIA USA KISS 'ORIENTING ARC LAMPS FOR LONGEST LIFE' *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6220740B1 (en) * 1993-10-20 2001-04-24 General Electric Company High efficiency dual output light source
US5530940A (en) * 1995-02-02 1996-06-25 Rohm And Haas Company Coupling device for light pipe system

Also Published As

Publication number Publication date
EP0501668A3 (en) 1993-03-17
JPH0582100A (ja) 1993-04-02

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