DIMMING CAP FOR A LAMP WITH TWO SEPARATE RADIATION SOURCES

Abstract

The invention refers to a dimming cap for a lamp with two separate radiation sources and, in particular, for a two-filament incandescent lamp, which has a concave shape with a base surface from which a circumferential side wall extends at least to a height H.sub.0 above the base surface, wherein the dimming cap, in a cross section formed at a height H.sub.0 parallel to the base surface, has a width (w.sub.0) that is constant within a tolerance of 0.1 mm over a first longitudinal section of the dimming cap, and which decreases over a second longitudinal section extending from the first longitudinal section to a first end of the dimming cap, and the height of the sidewall corresponds within a tolerance of 0.1 mm over the first longitudinal section to the constant height H.sub.0, wherein it increases over the second longitudinal section, wherein the first longitudinal section is between 70% and 98% of the length of the dimming cap in the cross-section formed at the height H.sub.0. The invention further refers to a lamp with such a dimming cap.

Claims

1. Dimming cap for a lamp with two separate radiation sources and, in particular, for a two-filament incandescent lamp, which has a concave shape with a base surface from which a circumferential side wall extends at least to a height H.sub.0 above the base surface, wherein the dimming cap, in a cross section formed at a height H.sub.0 parallel to the base surface, has a width (w.sub.0) that is constant within a tolerance of 0.1 mm over a first longitudinal section of the dimming cap, and which decreases over a second longitudinal section extending from the first longitudinal section to a first end of the dimming cap, and the height of the sidewall corresponds within a tolerance of 0.1 mm over the first longitudinal section to the constant height H.sub.0, wherein it increases over the second longitudinal section, characterized in that the first longitudinal section represents between 70% and 98% of the length of the dimming cap in the cross-section formed at the height H.sub.0.

2. Dimming cap according to claim 1, characterized in that the height of the side wall increases over the entire second longitudinal section.

3. Dimming cap according to claim 1, characterized in that the height H.sub.0 is between 1.8 and 3.6 mm, the length of the dimming cap is between 7 and 10 mm, and the width (w.sub.0) in the first longitudinal section is between 7.5 and 9.5 mm.

4. Dimming cap according to claim 1, characterized in that the height in the second longitudinal section increases to a value H.sub.1 that is between 3.8 and 4.4 mm.

5. Dimming cap according to claim 1, characterized in that the width (w.sub.0) decreases non-linearly over the second longitudinal section.

6. Dimming cap according to claim 1, characterized in that the height increases non-linearly within the second longitudinal section or over the entire second longitudinal section.

7. Dimming cap according to claim 1, characterized in that the width (w.sub.0) of the dimming cap, in the cross-section formed at the height H.sub.0 parallel to the base surface, decreases over a third longitudinal section extending from the first longitudinal section to a second end of the dimming cap being opposite the first end.

8. Lamp with two separate radiation sources and, in particular, a two-filament incandescent lamp for motor vehicles or two-wheeled vehicles with two filaments, wherein a dimming cap according to claim 1 is arranged at one of the two radiation sources.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The proposed dimming cap will be briefly explained again below with reference to exemplary embodiments in conjunction with the drawings, wherein:

[0011] FIG. 1 shows a schematic representation of a first embodiment of the proposed dimming cap in cross-section at the height H.sub.0;

[0012] FIG. 2 shows the dimming cap of the first exemplary embodiment in cross-section perpendicular thereto;

[0013] FIG. 3 shows a schematic representation of a second embodiment of the proposed dimming cap in cross-section at the height H.sub.0;

[0014] FIG. 4 shows the dimming cap of the second embodiment in cross-section perpendicular thereto; and

[0015] FIG. 5 shows a schematic representation of the arrangement of the proposed dimming cap in a two-filament incandescent lamp.

IMPLEMENTING THE INVENTION

[0016] FIG. 1 shows a section through a dimming cap 1 in a first embodiment of the present invention in a schematic representation. This section is parallel to the base surface of the dimming cap 1 at the height H.sub.0. In the section, therefore, a circumferential side wall 2 may be seen, which has a constant width w.sub.0 over a first longitudinal section L.sub.1 of the length L of the dimming cap 1. As may be seen in the figure, this width then decreases over the remaining second longitudinal section L.sub.2 to a first end of the dimming cap. In the present example, the width w remains constant over an extent of about 90% and then decreases over the last 10% of the length L of the dimming cap 1. A third longitudinal section L3 may also extend between the first longitudinal section L.sub.1 and the second end of the dimming cap, which third section serves for the rounding of corners as shown in FIG. 1.

[0017] FIG. 2 shows a cross-section perpendicular to the cross-sectional plane of FIG. 1 through the middle or longitudinal axis of the dimming cap 1. In this figure, the base surface 3 and the side wall 2 may be seen in cross-section. The dashed line shows schematically the course of the upper edge of the side wall 2 outside this cross-sectional plane. It may be seen from this figure that the side wall 2 has a constant height H.sub.0 over the first longitudinal section L.sub.1 and only increases in height in the second longitudinal section L.sub.2. The height H.sub.1 is reached at the top of the dimming cap 1.

[0018] FIG. 3 shows a further exemplary embodiment of a dimming cap 1 in a schematic illustration, again in cross-section parallel to the base surface at a height H.sub.0. In this example, the width w of the dimming cap has already decreased by some 70% of the total length L of the dimming cap.

[0019] FIG. 4 again shows the cross-section perpendicular to the cross-sectional plane of FIG. 3. In this figure may be seen the constant height H.sub.0 of the side wall over the longitudinal section L1 as well as an adjoining short section region in the longitudinal section L2. Only at the end of the dimming cap 1 does the height H of the side wall increase up to a final value H.sub.1 at the top of the dimming cap 1. There is a small transition region between the segments for the dipped beam and high beam in the headlight due to the long horizontal course of the upper edge of the side wall 2 in both embodiments. As a result, losses in the generation of the dipped beam and high beam are minimized. Exemplary dimensions of the proposed dimming cap are in the range between 7 and 10 mm for the length L of the dimming cap, in the range between 1.8 and 3.6 mm for the height H.sub.0, in the range between 7.5 and 9.5 mm for the constant width w.sub.0, and in the range between 3.8 and 4.4 mm at the height H.sub.1 at the top of the dimming cap.

[0020] Finally, FIG. 5 shows in highly schematic form, a two-filament incandescent lamp with an embodiment of the proposed dimming cap in plan view. Two filaments 4, 5 may be seen in the figure, wherein the filament 4 arranged on the left in the figure is for the generation of the high beam, while the filament 5 arranged on the right is for the generation of the dipped beam. The proposed dimming cap 1 is arranged on the right filament 5 in order to shade the light emission of this filament 5 in the lower half.

LIST OF REFERENCE NUMBERS

[0021] 1 dimming cap [0022] 2 side wall [0023] 3 base surface [0024] 4 filament for high beam [0025] 5 filament for dipped beam [0026] L length of the dimming cap [0027] L.sub.1 first longitudinal section [0028] L.sub.2 second longitudinal section [0029] L.sub.3 third longitudinal section [0030] w width of the dimming cap [0031] w.sub.0 constant width of the dimming cap [0032] H.sub.0 constant height of the side wall [0033] H.sub.1 height of the side wall at the top of the dimming cap