Illumination – Supported by vehicle structure – Projection-type headlamp
Reexamination Certificate
2000-07-14
2002-12-17
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Projection-type headlamp
C362S539000
Reexamination Certificate
active
06494603
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a projector-type headlamp for a vehicle, and more particularly to a low-beam headlamp.
BACKGROUND OF THE INVENTION
In recent years, projector-type headlamps have come to be frequently adopted as headlamps for vehicles.
As shown in
FIG. 1
, a projector-type headlamp comprises a light source
102
disposed on an optical axis Ax of the headlamp which extends in the longitudinal direction of a vehicle, a reflector
104
for reflecting light from this light source
102
in a forward direction close to the optical axis Ax, and a focusing lens
106
disposed forwardly of the reflector
104
.
Further, for using this projector-type headlamp as a low-beam headlamp, a light shielding plate
108
is provided between the focusing lens
106
and the reflector
104
. The shielding plate
108
eliminates upwardly illuminating light by shielding part of the reflected light from the reflector
104
. As a result, a luminous intensity distribution pattern P is formed for low beam light, showing a light-dark borderline CL, as shown in FIG.
2
.
Since the upwardly illuminating light of such a projector-type headlamp is eliminated almost completely by the light shielding plate
108
, an overhead sign installed above the road surface ahead of the vehicle cannot often be seen clearly.
Accordingly, an approach has been adopted, as shown in
FIG. 3
, to attach in the vicinity of an upper edge
108
a
an L-shaped plate
110
extending diagonally downward from a front surface
108
b
of the light shielding plate
108
. Reflected light from the reflector
104
is deflected or reflected upward by an upper inclined surface
110
a
of the L-shaped plate
110
. The reflected upward light propagates from the focusing lens
106
to illuminate overhead signs.
However, with the projector-type headlamp, a focal position of the focusing lens
106
is generally set at the upper edge
108
a
of the light shielding plate
108
. The L-shaped plate
110
is attached to the front surface
108
b
of the light shielding plate
108
near the upper edge. Therefore, when the headlamp is viewed from a forward and slightly upper direction, the L-shaped plate
110
is seen enlarged by the lens action of the focusing lens
106
, as shown in FIG.
4
. External light causes the upper inclined surface
110
a
of the L-shaped plate
110
to be seen as brightly lit, while a front-end surface
110
b
of the L-shaped plate
110
remains dark. Hence, the visual appearance of the headlamp is degraded when exposed to external light.
SUMMARY OF THE INVENTION
The invention of this application has been devised in view of the above-described circumstances. The object is to provide a projector-type headlamp for a vehicle capable of obtaining light for illuminating overhead-signs without impairing the appearance of the headlamp.
In embodiments of the invention, the above object is attained by providing a structure for illuminating overhead signs.
An embodiment of the invention provides a projector-type headlamp for a vehicle comprising: a light source disposed on an optical axis of the headlamp extending in a longitudinal direction of a vehicle; a reflector for reflecting light from the light source in a forward direction close to the optical axis; a focusing lens disposed forwardly of the reflector; and a light shielding plate interposed between the focusing lens and the reflector so as to eliminate upward illuminating light by shielding part of the reflected light from the reflector, wherein a projection, which has an upper inclined surface extending diagonally downward in a forward direction and is adapted to deflect or reflect reflected light from the reflector upwardly at the upper inclined surface, is integrally formed at a front surface of the light shielding plate and at a position in a vicinity of a upper edge thereof, and a front-end portion of the projection is formed with a curved surface in such a manner as to be smoothly connected to the upper inclined surface.
The phrase “deflect or reflect . . . upwardly” means to deflect or reflect the reflected light from the reflector incident upon the upper inclined surface of the projection such that an angle of downward inclination of the reflected light becomes small, but does not necessarily mean to reflect the light upward.
As long as the aforementioned “projection” is capable of deflecting or reflecting the reflected light from the reflector in an upwardly direction and capable of allowing the light for illuminating overhead-signs to propagate from the focusing lens, an arrangement of the upper inclined surface, including its planar shape, size, the angle of downward inclination and the like, should not be limiting.
The projector-type headlamp in accordance with an embodiment of the invention is arranged such that a projection having an upper inclined surface extending diagonally downward in a forward direction is integrally formed at a front surface of the light shielding plate and in the vicinity of an upper edge of the plate, and the reflected light from the reflector is deflected or reflected upwardly from the upper inclined surface. Accordingly, light for illuminating overhead-signs can propagate from the focusing lens.
When the headlamp is observed from a forward and slightly upper direction, the projection is seen enlarged by the lens action of the focusing lens. However, when the headlamp is exposed to external light, since the front-end portion is formed with a curved surface and smoothly connected to the upper inclined surface, the front-end portion does not appear as dark relative to the upper inclined surface which is seen as brightly lit by the external light. The front-end portion can be seen as being lit with the brightness changing gradually. Moreover, since the projection is formed integrally with the light shielding plate, its front-end portion can be easily formed with a curved surface. Further, compared to the L-shaped plate attached to the light shielding plate in a conventional manner, the projection's portion connected to the general portion of the light shielding plate can be seen as integrated and uniform in terms of its external appearance.
Therefore, it is possible to provide a projector-type headlamp for a vehicle capable of generating light for illuminating overhead-signs without impairing the appearance of the headlamp.
In addition, the portion of the light shielding plate in the vicinity of its upper edge is expected to reach a high temperature since the reflected light from the reflecting surface of the reflector is concentrated there. Also, the temperature of the projection is expected to become high. However, since the projection is formed integrally with the light shielding plate, the projection is unlikely to undergo thermal deformation, and the heat from the light shielding plate can be efficiently dissipated through the projection.
Further, although the angle of downward inclination of the upper inclined surface is not limiting as described above, if the angle of downward inclination is set to 25 to 35°, the illuminating light can propagate from the focusing lens at an angle of upward inclination suitable for illuminating the overhead signs. The reason for the 25° lower-limit is that if it is set to less than 25°, the light from the upper inclined surface and a; through the focusing lens may be directed upward to a region above the overhead sign. On the other hand, the reason for the 35° upper-limit is that if it is set to more 35°, the light from the upper inclined surface and through the focusing lens may be directed downward to a region below the overhead sign.
The aforementioned “upper inclined surface” may be one whose rear-end portion extends up to the front surface of the light shielding plate or one whose rear-end portion extends halfway. Whichever case, the line of intersection between the upper inclined surface or its rearwardly extending surface and the front surface of the light shielding plate is preferably set at a position 0.5 to 3.0 mm below the upper edge of the light shielding p
Fish & Richardson P.C.
Koito Manufacturing Co. Ltd.
O'Shea Sandra
Truong Bao
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