Illumination – Supported by vehicle structure – Projection-type headlamp
Reexamination Certificate
1999-11-12
2001-12-04
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Projection-type headlamp
C362S507000, C362S509000, C359S613000
Reexamination Certificate
active
06325529
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a vehicle headlamp fitted with a shade.
Many vehicle headlamps are often fitted with shades in order to avoid causing oncoming vehicle drivers and pedestrians to be blinded by the glare of headlamps.
As shown in
FIG. 5
, a shade
2
is arranged so that direct light from a light bulb
4
is shielded by a shielding cap
2
a.
When a reflector
6
has a reflective surface
6
a
extending forward from the upper end edge of the reflector
6
as shown in
FIG. 5
, shielding of direct light incident on the upper wall surface
6
b
from the light source bulb
4
is desirable in view of preventing the generation of stray light as a glaring source.
Therefore, it has heretofore been contrived to block light incident on the upper wall surface
6
b
by forming the upper end portion
2
b
of the shielding cap
2
a
so that the upper end portion
2
b
may be extended backward further than the other portion as shown in FIG.
5
.
In a case where the reflective surface of the reflector is constituted of a plurality of reflective elements, however, the reflective surface has irregularities on a reflective element basis. Consequently, only forming the rear end edge of the upper end portion of the shielding cap into a simply curved shape as before cannot stop the incidence of light on the upper wall surface
6
b
without impeding the incidence of light on the reflective surface
6
a.
In other words, a problem develops from the fact that if it is attempted to prevent the generation of such stray light in the conventional vehicular headlamp, utilization luminous flux (the amount of light incident on the reflective surface
6
a
) may largely be decreased, whereas if it is attempted not to greatly decrease the utilization luminous flux, a large amount of stray light may be generated.
SUMMARY OF THE INVENTION
An object of the present invention made in view of the foregoing problems is to provide such a vehicular headlamp with a shade that even though the reflective surface of a reflector is constituted of a plurality of reflective elements, the generation of stray light is minimized while a decrease in utilization luminous flux is reduced to the minimum.
The present invention is intended to accomplish the object above by contriving to provide a novel configuration for the rear end edge of the upper end portion of a shielding cap.
According to the present invention, a vehicular headlamp comprises a light source bulb, a reflector having a reflective surface for reflecting light from the light source bulb forward and an upper wall surface extending forward from the upper end edge of the reflective surface, an area near the upper end edge of the reflective surface is divided into a plurality of vertically-striped reflective elements, and a shade having a shielding cap for shielding the direction light directed forward from the light source bulb, in that the rear end edge of the upper end portion of the shielding cap is set to have a curved configuration substantially similar to a curved configuration obtainable from a line of intersection between a curved plane forming the upper end portion of the shielding cap and an imaginary curved plane formed by connecting together the light emission center of the light source bulb and the upper end edge of each reflective element.
On condition that the area near the upper end edge of the “reflective surface” is constituted of the plurality of divided vertically-striped reflective elements, any area other than the area near the upper end edge thereof may be constituted of a plurality of reflective elements or formed of a single curved plane such as a rotary parabolic plane or the like.
The configuration of the rear end edge of the portion other than the aforementioned “rear end edge of the upper end portion of the shielding cap” is not particularly restrictive.
As shown by the arrangement above, since the area near the upper end edge of the reflective surface of the reflector is constituted of the plurality of divided vertically-striped reflective elements according to the present invention, the upper end edge (i.e., a line of intersection between the reflective surface and the upper wall surface) of the reflective surface has the curved configuration having irregularities in the respective reflective elements. However, the rear end edge of the upper end portion of the shielding cap of the shade is set to have a curved configuration substantially similar to the curved configuration obtained from the line of intersection between the curved plane forming the upper end portion and the imaginary curved plane formed by connecting together the light emission center of the light source bulb and the upper end edge of each reflective element, whereupon the incidence of light on the upper wall surface can be stopped substantially without impeding the incidence thereof on the reflective surface.
Therefore, even in the case where the reflective surface is constituted of the plurality of reflective elements in the vehicular headlamp fitted with the shade according to the present embodiment of the invention, the generation of stray light can be minimized while a decrease in utilization luminous flux is reduced to the minimum.
Although the configuration of the curved plane forming the aforementioned “upper end portion of the shielding cap” is not particularly restrictive, formation of the curved plane forming the upper end portion thereof into the substantially horizontal plane in the area near the rear end edge of the upper end portion of the shielding cap makes it possible to not only relatively easily calculating the line of intersection between both the aforementioned curved planes but also machining the rear end edge of the upper end portion of the shielding cap.
REFERENCES:
patent: 4882660 (1989-11-01), Liverance et al.
patent: 5130904 (1992-07-01), Ohshio et al.
patent: 5567033 (1996-10-01), Tanaka et al.
patent: 5611612 (1997-03-01), Choji et al.
patent: 5879073 (1999-03-01), Hori et al.
patent: 6132068 (2000-10-01), Katsumata
Fish & Richardson P.C.
Koito Manufacturing, Inc., Ltd.
Negron Ismael
O'Shea Sandra
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