EP0104798A1 - Leuchte - Google Patents

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Publication number
EP0104798A1
EP0104798A1 EP83305060A EP83305060A EP0104798A1 EP 0104798 A1 EP0104798 A1 EP 0104798A1 EP 83305060 A EP83305060 A EP 83305060A EP 83305060 A EP83305060 A EP 83305060A EP 0104798 A1 EP0104798 A1 EP 0104798A1
Authority
EP
European Patent Office
Prior art keywords
light
portions
lamp unit
focus
reflector
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Withdrawn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
EP83305060A
Other languages
German (de)
English (en)
Inventor
Stephen Leslie Law
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.)
ZF International UK Ltd
Original Assignee
Lucas Industries 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 Lucas Industries Ltd filed Critical Lucas Industries Ltd
Publication of EP0104798A1 publication Critical patent/EP0104798A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21SNON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S43/00Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights
    • F21S43/20Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by refractors, transparent cover plates, light guides or filters
    • F21S43/255Filters

Definitions

  • This invention relates to a lamp unit, particularly though not exclusively for use on a road vehicle.
  • Our U.K. Patent No. 1591013 describes a lamp unit which is generally of the type shown in schematic cross-section in Figure 1 of the accompanying drawings.
  • the lens element 12 includes a multiplicity of individual lenses 13 each of which focusses a respective pencil of light rays through a respective light-transmitting interstice 14 of an otherwise opaque baffle 15 which is disposed on the opposite side of the lens element 12 to the light bulb 10.
  • Each of the interstices 14 is located on the optical axis of the respective lens 13 and is limited in its extent to that necessary to transmit substantially the whole of the pencil of light rays focussed by that lens 13.
  • the divergent light emerging from the baffle 15 is re-directed and/or re-distributed by lensing 16 on a light-transmitting cover 17 which forms an external surface of the lamp unit.
  • the above-described construction has two main advantageous features. Firstly, the amount of externally incident light which passes through the cover 17 and the baffle 15 to be reflected by the reflector 11 and re-emitted is small, due to the small size of the interstices 14 as compared with the baffle 15 as a whole. Accordingly, the risk of so-called "phantom" signals is substantially reduced. Secondly, the presence of the baffle 15 obscures the internal components of the lamp unit (i.e. the light bulb 10, the reflector 11 and the lens unit 12) whilst not substantially reducing the intensity of the light transmitted from the lamp unit by the light bulb.
  • the lamp unit i.e. the light bulb 10, the reflector 11 and the lens unit 12
  • the aesthetic appearance of the lamp unit is improved, and it is possible to make the lamp unit of the so-called "indescernible” type, i.e. where the lamp unit normally has the appearance of a decorative panel and only becomes visible when the light bulb is energised.
  • the baffle 15 does not significantly reduce the intensity of the light emitted from the bulb 10, it is important that the light rays reaching the lens element 12 are substantially mutually parallel so that they may easily be focussed through the baffle interstices 14. Accordingly, it is the usual practice to make the reflector 11 of parabolic or paraboloidal form and to mount the light bulb 10 such that an incandescent filament 18 thereof is positioned on the focal point of the parabola or paraboloid. Whilst this arrangement is perfectly satisfactory for light bulbs having only a single incandescent filament, problems arise where for example a twin-filament bulb is employed since only one of these filaments can be positioned exactly on the focal point. Therefore the light rays emitted by the other filament will not necessarily be mutually parallel when they reach the lens element 12 after reflection by the reflector 11, and may not be focussed properly through the baffle interstices 14.
  • a lamp unit includes a reflector whose reflective surface is composed of a plurality of first portions which all lie substantially on a geometrical surface having a first focus and a plurality of second portions which all lie substantially on a further geometrical surface having a second focus which is displaced from the first focus, the first and second portions alternating with each other over the area of the reflector in at least one given direction, and a bulbholder which in use receives a twin incandescent filament assembly such that said filaments are positioned on the first and second foci respectively
  • the lamp unit also includes a lens element overlying the reflector and having a multiplicity of individual lenses, and a baffle disposed on the opposite side of the lens element to the bulbholder and including a plurality of light-transmitting portions each of which is located on the optical axis of a respective one of the lenses, the remainder of the baffle being light-absorbing or opaque, each lens being arranged to focus a pencil of light rays through the respective light-transmitting portion of the baffle and the light-transmitting portion being limited in its extent to that necessary to transmit substantially the whole of the pencil of light rays.
  • the lamp unit may further include a light-transmitting cover which is disposed on the opposite side of the baffle to the lens element and which is provided with lensing to re-direct and/or redistribute the light emerging from the baffle.
  • first and second portions are arranged generally radially with respect to the first and second foci such that they alternate with each other in a circumferential direction.
  • the lamp unit is a combined stop and tail light unit for use on a road vehicle
  • the total area of those portions of the reflector having the filament for the stop function at their focus is greater than the total area of those portions having the filament for the tail light function at their focus.
  • Figures 2 to 4 show a reflector body 20 which is generally of dished configuration and which is of rectangular shape when viewed head-on (although the invention is equally applicable to other shapes of reflector bodies).
  • a reflecting surface 21 of the body 20 is composed of a plurality of first portions 22 which all lie on a first paraboloidal surface whose focus is indicated at 23, and a plurality of second portions 24 which all lie on a second paraboloidal surface whose focus is indicated at 25.
  • the focus 25 is displaced from the focus 23 by a distance a in a direction perpendicular to the major axes of the two paraboloids and by a distance b in a direction parallel to those axes (see Figure 3).
  • the portions 22 and 24 are disposed radially of the paraboloid axes such that they alternate with each other in a circumferential direction (i.e. circumferentially around the paraboloid axes).
  • the portions 22 are indicated by hatching in Figure 2.
  • the reflecting surface 21 is punctuated at a generally central position by a circular opening 26 defined by a tubular spigot 27.
  • a bulbholder 27a Received in the interior of the spigot 27 is a bulbholder 27a which is capable of micromanipulation and which receives in use a twin-filament light bulb 28.
  • the light bulb is mounted such that one of its incandescent filaments (referenced 29) is positioned on the focus 23 while the other filament 30 is positioned on the focus 25.
  • the light bulb is energised, light emitted by the filament 29 and falling on the portions 22 of the reflecting surface 21 will be reflected by the latter as mutually parallel rays, as will light emitted by the filament 30 and falling on the portions 24.
  • mutually parallel light rays will be obtained irrespective of which of the filaments 29 and 30 is energised at any particular time.
  • the major axes of the two paraboloidal surfaces will be mutually parallel, so that the light rays emitted by the filament 29 and reflected by the portions 22 will be parallel to the light rays emitted by the filament 30 and reflected by the portions 24.
  • the reflector body 29 is incorporated into the type of lamp unit shown in Figure 1, since then the light rays will be properly focussed through the baffle interstices irrespective of which filament 29 or 30 is energised.
  • those parts in common with the lamp unit of Figure 1 are designated by the same reference numerals but with 100 added.
  • the reflector body 20 forms part of a combined stop and tail light unit for a road vehicle.
  • the filament 29 of the light bulb 28 performs the "stop" function and that the filament 30 provides the tail light function.
  • the ratio of the total area of the portions 22 to the total area of the portions 24 is chosen to be 1.4:1.
  • the reflecting surface 21 is divided into thirty portions 22 each having an angular extent ( , Figure 2) of 7° and thirty portions 24 each having an angular extent 2 of 5°.
  • the dimensions of the reflecting surface 21 as viewed head-on are 65mm width by 100mm breadth, and the focal length of each paraboloidal surface is 18mm, giving light collection over a solid angle of 2.4 steradians for the filament 29 and over a solid angle of 2.4 steradians for the filament 30.
  • the total area of the portions 22 or the total area of the portions 24 is rather less than the overall area of the whole reflecting surface 21, any loss in light-gathering power can easily be compensated by increasing the reflection efficiency of the portions 22 and 24.
  • these portions can be metallised in aluminium.
  • the portions 22 and 24 lie on identical paraboloidal surfaces whose foci are spaced from one another, and in a region indicated generally at 31 in Figure 2 these surfaces intersect one another. In order to simplify manufacture of the reflector body 20, the portions 22 and 24 may merge into a common surface in this region.
  • the portions 22 and 24 have been described above as alternating circumferentially of the paraboloid axes, so that each portion is oriented generally radially of those axes.
  • This particular arrangement has the advantage that side walls 32 (see Figure 5) which link each portion 22 with the adjacent portions 24 can be made near-perpendicular to a plane at right-angles to the paraboloidal axes, to facilitate production of the body 20 by moulding.
  • Other arrangements can however be employed in which the portions 22 and 24 alternate with each other in a direction other than a circumferential one, although in this case the body 20 will probably have to be produced using more complicated manufacturing techniques.
  • the reflector body 20 has been described as being suitable for incorporation into a lamp unit of the type shown in Figure 1, it will be appreciated that the invention is much more widely applicable than this, and that the reflector body can be included in any suitable type of lamp unit which employs a twin-filament light bulb.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
EP83305060A 1982-09-23 1983-09-01 Leuchte Withdrawn EP0104798A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8227111 1982-09-23
GB8227111 1982-09-23

Publications (1)

Publication Number Publication Date
EP0104798A1 true EP0104798A1 (fr) 1984-04-04

Family

ID=10533112

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83305060A Withdrawn EP0104798A1 (fr) 1982-09-23 1983-09-01 Leuchte

Country Status (5)

Country Link
EP (1) EP0104798A1 (fr)
JP (1) JPS5978442A (fr)
AU (1) AU1938683A (fr)
BR (1) BR8305157A (fr)
YU (1) YU191783A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2654802A1 (fr) * 1989-11-22 1991-05-24 Dilouya Gilbert Feu de signalisation de surface reduite pour vehicule automobile.
DE19852311A1 (de) * 1998-11-12 2000-05-18 Volkswagen Ag Rückleuchteneinheit für ein Fahrzeug und Schaltungsanordnung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2140165A1 (de) * 1971-08-11 1973-02-22 Reitter & Schefenacker Kg Reflektor, insbesondere fuer kraftfahrzeugleuchten
GB1591013A (en) * 1978-05-30 1981-06-10 Lucas Industries Ltd High contrast lamp assembly

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2140165A1 (de) * 1971-08-11 1973-02-22 Reitter & Schefenacker Kg Reflektor, insbesondere fuer kraftfahrzeugleuchten
GB1591013A (en) * 1978-05-30 1981-06-10 Lucas Industries Ltd High contrast lamp assembly

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2654802A1 (fr) * 1989-11-22 1991-05-24 Dilouya Gilbert Feu de signalisation de surface reduite pour vehicule automobile.
DE19852311A1 (de) * 1998-11-12 2000-05-18 Volkswagen Ag Rückleuchteneinheit für ein Fahrzeug und Schaltungsanordnung
US6508577B2 (en) 1998-11-12 2003-01-21 Volkswagen Ag Rear light unit for a vehicle and circuit therefor

Also Published As

Publication number Publication date
JPS5978442A (ja) 1984-05-07
YU191783A (en) 1987-10-31
BR8305157A (pt) 1984-05-02
AU1938683A (en) 1984-03-29

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Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB IT

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19841204

RIN1 Information on inventor provided before grant (corrected)

Inventor name: LAW, STEPHEN LESLIE