Illumination – Supported by vehicle structure – Adjustable lamp or lamp support
Reexamination Certificate
2002-05-10
2003-10-21
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Adjustable lamp or lamp support
C362S517000, C362S464000, C362S512000, C362S529000, C362S233000, C362S297000, C362S350000
Reexamination Certificate
active
06634778
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a multi-lamp type vehicular headlamp.
A vehicular headlamp is commonly capable of selectively switching between a low-beam light distribution pattern and a high-beam light distribution pattern. It is difficult for a vehicular headlamp having fixed light distribution patterns to produce a beam with a light distribution pattern which is always optimal for the instant operating conditions of the vehicle.
In view of this problem, a vehicular headlamp has been proposed which forms a synthesized light distribution pattern of beams emitted from a plurality of lamp fixture units and wherein at least one of the lamp fixture units is pivoted as appropriate according to the operating conditions of the vehicle (e.g., steering angle and speed) so that a beam can be produced with a synthesized light distribution pattern which varies according to the operating conditions of the vehicle.
FIG. 6
is a front view of a vehicular headlamp
110
, which is a specific example of such a vehicular headlamp, and
FIG. 7
is a perspective view of a synthesized light distribution pattern that is emitted ahead of the vehicle from the vehicular headlamp
110
while the vehicle is turning left.
As shown in these two drawings, the vehicular headlamp
110
has a headlamp unit
116
for emitting a low beam with a basic light distribution pattern P′ having a horizontal cutoff line CL
1
′ and an oblique cutoff line CL
2
′, and a pair of auxiliary lamp fixture units
118
,
120
for emitting beams with respective auxiliary light distribution patterns P
1
′, P
2
′ that partially reinforce the brightness of the basic light distribution pattern P′. By pivoting the auxiliary lamp fixture units
118
,
120
about respective vertical axes A
1
′, A
2
′ to move the auxiliary light distribution patterns P
1
′, P
2
′ as appropriate in the horizontal direction, the vehicular headlamp
110
will provide a beam with a synthesized light distribution pattern which varies according to the operating conditions of the vehicle.
However, this vehicular headlamp
110
has certain problems. For example, as shown in
FIG. 7
, when the auxiliary light distribution pattern P
2
′ formed under the oblique cutoff line CL
2
′ moves away from the center of the basic light distribution pattern P′ to form a pattern P
2
″, the hot zone HZ′ of the basic light distribution pattern P′ and the hot zone HZ
2
′ of the auxiliary light distribution pattern P
2
″ become separated from each other. As a result, the road surface ahead of the vehicle becomes relatively dark in the region between the hot zones HZ′, HZ
2
′ due to contrast with the hot zones HZ′, HZ
2
′, thereby significantly degrading the visibility of that region of the road surface.
SUMMARY OF THE INVENTION
The present invention is made in view of the above problem, and it is an object of the present invention to provide a vehicular headlamp capable of moving an auxiliary light distribution pattern in the horizontal direction by pivoting an auxiliary lamp fixture unit and which is capable of effectively suppressing degradation in the visibility of the road surface ahead of the vehicle caused by movement of the auxiliary light distribution pattern.
The present invention achieves the above object by appropriate selection of the pivot direction of the auxiliary lamp fixture unit.
More specifically, a vehicular headlamp according to the present invention includes: a headlamp unit for emitting a beam with a prescribed basic light distribution pattern, and an auxiliary lamp fixture unit for emitting a beam with an auxiliary light distribution pattern that partially reinforces the brightness of the basic light distribution pattern, the auxiliary lamp fixture unit being supported so that it is pivotable about a prescribed pivot axis to move the auxiliary light distribution pattern in a horizontal direction. The above vehicular headlamp is characterized in that the pivot axis is tilted at a prescribed angle with respect to a vertical direction so that the auxiliary light distribution pattern is displaced upward when it is moved away from the center of the basic light distribution pattern.
The headlamp unit and auxiliary lamp fixture unit are not particularly limited in terms of their specific structures. For example, a parabolic lamp fixture unit or a projector-type lamp fixture unit may be employed. Moreover, the light sources of the headlamp unit and auxiliary lamp fixture unit are not particularly limited in terms of their specific structures. For example, a discharge light-emitting portion of a discharge bulb or a filament of an incandescent bulb such as halogen bulb may be employed.
According to the above structure, in the vehicular headlamp of the present invention, the auxiliary lamp fixture unit is supported so that it is pivotable about a prescribed pivot axis to move in the horizontal direction the auxiliary light distribution pattern that is formed by a beam emitted from the auxiliary lamp fixture unit. Moreover, the pivot axis is tilted at a prescribed angle with respect to the vertical direction so that the auxiliary light distribution pattern is displaced upward when moved away from the center of the basic light distribution pattern that is formed by a beam emitted from the headlamp unit. As a result, the following effects can be obtained:
As the auxiliary light distribution pattern is moved away from the center of the basic light distribution pattern, the hot zone of the auxiliary light distribution pattern may be separated away from the hot zone of the basic light distribution pattern. However, since the hot zone of the auxiliary light distribution pattern is displaced upward at this time, the position of this hot zone on the road surface ahead of the vehicle is shifted away from the vehicle. As a result, the illumination intensity of this hot zone on the road surface ahead of the vehicle is reduced sharply. Since the two hot zones do not concurrently reside on both sides of the road surface ahead of the vehicle, the road surface ahead of the vehicle is prevented from becoming relatively dark in the region between the hot zones due to contrast with the hot zones.
Thus, according to the present invention, a vehicular headlamp is realized which is capable of moving the auxiliary light distribution pattern in a horizontal and upward direction by pivoting the auxiliary lamp fixture unit and which therefore effectively significantly reduces any degradation in visibility of the road surface ahead of the vehicle caused by movement of the auxiliary light distribution pattern.
The auxiliary light distribution pattern is moved away from the center of the basic light distribution pattern mainly in order to improve the visibility ahead of the vehicle when the vehicle turns right or left. Displacing the auxiliary distribution pattern upward as in the present invention enables the road surface away from the vehicle to be illuminated, thus causing the visibility of the road surface ahead of the vehicle to be effectively improved.
The basic light distribution pattern is not particularly limited in terms of its specific composition. When the basic light distribution pattern is a low-beam light distribution pattern having a horizontal cutoff line and an oblique cutoff line, a hot zone is formed in a region relatively close to the vehicle on the road surface ahead of the vehicle. It is therefore particularly effective to use the structure of the present invention which is capable of preventing the road surface ahead of the vehicle from becoming relatively dark in the region between the hot zones. In this case, when the auxiliary lamp fixture unit forms the auxiliary light distribution pattern under the oblique cutoff line, the tilt angle of the pivot axis of the auxiliary lamp fixture unit with respect to the vertical direction may be smaller than the angle at which the oblique cutoff line is tilted upward. As a
Koito Manufacturing Co. Ltd.
O'Shea Sandra
Tsidulko Mark
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