Vibration resistant automotive front lighting lamp

Abstract

A lamp for automotive front lighting and a vehicle headlight comprising the lamp are described, as well as a method of manufacturing the lamp. The lamp 10 comprises a base 12 for mechanical and electrical connection to an automotive headlight 50. A burner 14 is fixed to the base 12 and comprises an enclosed transparent vessel 22. A first filament 34 is arranged within the vessel 22. A holding wire 30c is arranged within the vessel, and a baffle 40 is arranged proximate to the first filament 34 to partially shield light emitted from the first filament 34. The baffle 40 is fixed to the holding wire 30c. The transparent vessel 22 comprises a vessel wall including a cylindrical portion 24 surrounding the first filament 34. In order to obtain a lamp which may withstand vibration, the vessel wall comprises, within the cylindrical portion 24, a deformed material portion 38 which contacts the baffle 40 or the holding wire 30c. The deformed material portion 38 is shielded from the first filament 34 by the baffle 40. During manufacture, the first filament 34, the baffle 40 and the holding wire 30c are inserted into the vessel 22, and the vessel wall is deformed to provide the deformed material portion 38.

Claims

1. Lamp for automotive vehicle front lighting, comprising a base for mechanical and electrical connection to an automotive headlight, a burner fixed to said base, said burner comprising a sealed transparent vessel, at least a first filament arranged within said vessel, at least one holding wire arranged within said vessel, and a baffle arranged proximate to said first filament to partially shield light emitted from said first filament, said baffle being fixed to said holding wire, where said transparent vessel comprises a vessel wall including a cylindrical portion surrounding said first filament, and where said vessel wall comprises, within said cylindrical portion, a deformed material portion which contacts said baffle or said holding wire, where said deformed material portion is shielded from said first filament by said baffle.

2. Lamp according to claim 1, wherein said baffle includes an inner side facing said first filament and an outer side arranged opposite to said inner side, where said deformed material portion is arranged to contact said outer side of said baffle, or said holding wire on said outer side of said baffle.

3. Lamp according to claim 1, wherein said deformed material portion at least partially encloses said holding wire.

4. Lamp according to claim 1, wherein said holding wire comprises a free end projecting from a fixing position of said baffle, wherein said deformed material portion at least partially encloses said free end of said holding wire.

5. Lamp according to claim 1, further comprising at least a second filament arranged within said vessel.

6. Lamp according to claim 5, wherein said deformed material portion is shielded from said second filament by said baffle.

7. Lamp according to claim 1, wherein at least three holding wires are arranged within said vessel, and said filaments and said baffle are fixed to said holding wires, where said holding wires extend from a pinch seal of said vessel into the interior of said vessel, and where a holding bar is arranged distant from said pinch seal, said holding bar enclosing said holding wires.

8. Lamp according to claim 1, wherein said base comprises three electrical contacts, and three holding wires are arranged extending from a pinch seal of said vessel into the interior of said vessel, each of said holding wires being electrically connected to one of said electrical contacts, where said first filament is electrically connected between a first and a third holding wire, and where a second filament is electrically connected between a second and said third holding wire.

9. Vehicle headlight, comprising a reflector, and a lamp according to claim 1.

10. Method of manufacturing a lamp for automotive vehicle front lighting, said lamp comprising a base for mechanical and electrical connection to an automotive headlight, said method comprising the steps of providing a transparent vessel comprising a vessel wall including a cylindrical portion, inserting at least a first filament and a baffle fixed to at least one holding wire into said vessel, such that said first filament is surrounded by said cylindrical portion of said vessel wall, deforming said vessel wall to provide, within said cylindrical portion, a deformed material portion which contacts said baffle or said holding wire, where said deformed material portion is formed at a position shielded from said first filament by said baffle.

11. Method according to claim 10, where said step of deforming said vessel wall includes heating said vessel wall at least to a softening temperature.

12. Method according to claim 10, further comprising deforming said vessel wall to form a pinch seal embedding said holding wire.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings

(2) FIG. 1 shows a perspective view of a lamp according to a first embodiment of the invention;

(3) FIG. 2 shows a side view of the lamp of FIG. 1 in the horizontal operating position;

(4) FIG. 3a shows an enlarged sectional view of a portion of the lamp of FIG. 1 with the section taken along line R in FIG. 1;

(5) FIG. 3b shows an enlarged sectional view of a portion of a second embodiment of a lamp;

(6) FIG. 4 shows in a schematic representation a vehicle headlight with a lamp according to FIGS. 1-3.

DETAILED DESCRIPTION OF EMBODIMENTS

(7) FIGS. 1, 2 show an automotive halogen lamp 10.

(8) The lamp 10 comprises a base 12 and a burner 14 fixed to the base 12.

(9) The base 12 comprises a positioning ring 16 which includes three positioning protrusions 18a, 18b radially protruding from the base 12 (of which only two are shown in FIG. 1). A reference plane for positioning is defined by the upper portions of the protrusions 18a, 18b, 18c.

(10) The lamp 10 may be fixed to a vehicle headlight so as symbolically shown in FIG. 4 at the protrusions 18a, 18b. The protrusion 18b serves as a reference protrusion defining a radial reference direction R. A symmetry plane is positioned to include a longitudinal axis X of the lamp 10, extending centrally through the positioning ring 16 perpendicular to the reference plane, and the radial reference direction R extending radially from the longitudinal axis X into the direction of the reference protrusion 18b.

(11) The burner 14 comprises a quartz glass vessel 22 with a central portion 24 of generally circular cylindrical shape (except for a deformation as will be described below). At the top, the otherwise transparent vessel 22 comprises a coated portion 26 which is opaque. At the bottom, the vessel 22 is sealed in a pinch seal 28, which is fixed to the base 12.

(12) Projecting from the pinch seal 28 into the interior of the vessel 22 are three holding wires 30a, 30b, 30c. The holding wires 30a, 30b, 30c are further fixed by a holding bar 32 made out of quartz glass material and arranged distant from the pinch seal 28. The holding wires 30a-30c are embedded within the material of the holding bar 32. Further, fixed to the holding wires 30a, 30b, 30c are arranged a first filament 34 (low-beam filament) and a second filament 36 (high-beam filament).

(13) Proximate to the first filament 34, a baffle 40 is arranged, welded to a third of the holding wires (30c). As shown, the baffle is provided to cover the axial extent of the first filament 34 and thus partially shield light emitted from the filament 34 into radial directions. Further, a front portion 42 of the baffle 40 is arranged in between the first and second filaments 34, 36 and therefore serves to shield the filaments 34, 36 from one another.

(14) As also shown in detail in the enlarged sectional view of FIG. 3a, the first, low beam filament 34 is connected at one end to a first holding wire 30a and at the other end to the baffle 40, which is welded to the third holding wire 30c. The second, high-beam filament 36 is fixed to a second holding wire 30b and to the third holding wire 30c. By these connections, the filaments 34, 36 are both mechanically held at defined positions within the vessel 22 and are electrically connected between the holding wires 30a, 30b, 30c. The holding wires, in turn, are connected internally within the base 12 to electrical contacts 20 protruding from the lower portion of the base 12. Thus, the filaments 34, 36 may be operated by supplying electrical power at the electrical contacts 20.

(15) FIG. 3a shows an enlarged sectional view of the central, circular-cylindrical portion 24 of the vessel 22. As shown, the filaments 34, 36 are each provided as a single winding structure of filament wire wound around a straight filament axis.

(16) In FIG. 3, the filament axis 35 of the first filament 34 and the filament axis 37 of the second filament 36 are arranged in parallel to the longitudinal axis X of the lamp 10.

(17) The baffle 40 comprises a bottom surface 41 from which a front surface 43, a back surface 47, and side surfaces 45 extend. The side surfaces 45 terminate in side edges 48. At the back surface 47, an attachment tab 52 is integrally formed.

(18) The attachment tab 52 serves to connect the filament wire of the first filament 34 to the baffle 40. It is arranged substantially flat in a plane that is oriented horizontally in FIG. 3. As shown, the filament wire of the first filament 34 is welded to the attachment tab 52.

(19) As shown in FIG. 2, FIG. 3a, the wall of the vessel 22 is deformed at a position located in the horizontal arrangement of FIG. 2, FIG. 3a below the baffle 40. A deformed material portion, or dimple 38 is formed in the wall of the vessel 22 to contact and partially enclose the third holding wire 30c. The dimple 38 may also contact the lower surface 41 of the baffle 40. The baffle 40 and the holding wire 30c are therefore mechanically held by the wall of the vessel 22, such that movement thereof relative to the vessel 22 is limited even under the application of forces of inertia due to vibration.

(20) During manufacture of the lamp 10, first the vessel 22 is formed without the pinch seal 28, i.e. open to the left in FIG. 2, FIG. 3. The holding wires 30a-30c with attached filaments 34, 36 and the baffle 40, connected together by the holding bar 32 are inserted into the interior of the vessel 22. By forming the pinch seal 28, the holding wires 30a-30c are embedded into the quartz glass material.

(21) In a further step, the deformation 38 is formed by heating the wall of the vessel at least locally to a softening temperature and impressing the dimple 38 such that the softened quartz glass material contacts the third holding wire 30c and at least partially encloses parts thereof, such that the holding wire 30c and the baffle 40 adhere to the deformation 38 thus obtained.

(22) In particular, the deformation 38 may be formed by gas pressure, namely by applying a vacuum at the tip of the lamp 10, such that atmospheric pressure at the exterior of the vessel 22 will form the dimple 38 at the locally heated position of the wall.

(23) In a further step, the interior of the vessel 22 is filled with a suitable filling for a halogen lamp with a filling gas of halogen and xenon and crypton as rare gas filling before the vessel 22 is closed off at the tip. The gas filling is provided such that the lamp at room temperature has a cold filling pressure of 1 Mpa.

(24) The position of the deformation 38 is chosen to be shielded from the first filament 34 by the baffle 40, i.e. the deformation 38 is located behind the baffle 40 as viewed from the first filament. Correspondingly, the optical distortion caused by the deformation 38 is minimal, because light emitted from the first filament 34 is shaded at the baffle 40 and does not directly reach the position of the deformation 38, whereas only a very small portion of light emitted from the second filament 36 passes through the wall of the vessel 22 at the position of the deformation 38.

(25) FIG. 3b shows an alternative embodiment in a view similar to FIG. 3a. The alternative embodiment largely corresponds to the previously described first embodiment, thus only differences will be explained.

(26) In the alternative embodiment, the holding wire 30c is provided longer such that a free end 31 projects from the point of contact to the baffle 40. The dimple 38 is formed at a position closer to the tip of the lamp, and encloses the free end 31 of the holding wire 30c.

(27) The alternative position of the dimple 38 as shown in FIG. 3b further has the advantage that the dimple 38 is shielded not only from direct light emitted from the first filament 34, but also from direct light emitted from the second filament 36. Thus, in the alternative embodiment optical distortion is further minimized.

(28) As shown in FIG. 3a, 3b, the axial length L.sub.1 of the first filament 34 entirely overlaps with the axial length L.sub.B of the baffle 40. Thus, a substantial portion of light emitted from the first filament 34 is shielded at the side edges 48 of the baffle 40, leading to a corresponding straight bright/dark cutoff.

(29) FIG. 4 shows schematically a headlight 50 where the lamp 10 as described above is schematically shown arranged within a reflector 46. Light emitted from the filaments 34, 36 (not shown in FIG. 3) is reflected by the reflector 46 to form different illumination beams. Light from the second (high-beam) filament 36 is shown as a dotted line to be reflected by both the upper and lower part of the reflector 46 to form a high-beam without a bright/dark cutoff.

(30) Light emitted from the first low-beam filament 34 is shown as a dashed line to be partially shielded by the baffle 40 such that only an upper portion of the reflector 46 is illuminated. The upper portion of reflector 46 is shaped to reflect the light from the first filament 34 to form an illumination beam with a horizontal bright/dark cutoff. In the resulting low beam, there is no distortion from the deformation 38, because of the position thereof behind the baffle 40.

(31) Arrangement of the filaments 34, 36 and of the baffle 40 is exactly symmetrical with regard to the symmetry plane defined by the axes R, X. Thus, the resulting beam patterns are symmetrical, too. In particular, the low-beam pattern will have a horizontal bright/dark cutoff.

(32) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiment.

(33) Variations from the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims the word “comprising” does not exclude other elements, and the indefinite articles “a” or “an” do not exclude a plurality.

(34) The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.