Electric lamp and discharge devices – With optical device or special ray transmissive envelope – Reflector
Reexamination Certificate
1999-11-18
2003-10-07
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With optical device or special ray transmissive envelope
Reflector
C313S579000, C313S113000, C313S316000
Reexamination Certificate
active
06630770
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention
The present invention relates to a light source bulb in automotive headlamps, such as two-lamp type halogen headlamps, in which a prescribed low beam distribution pattern and high beam distribution pattern each can be obtained by entire-surface reflection light distribution control of the reflecting surface of a reflector, the light source bulb being capable of use both as a light source bulb in an automotive headlamp for right traffic and a light source bulb in an automotive headlamp for left traffic in one, without causing a problem of virtual image glare.
Incidentally, as employed in the present specification document and the accompanying drawings, the symbol “A” represents the front as seen from the driver-side along the traveling direction of an automobile. As seen in the same manner, the symbol “B” represents the back, the symbol “L” the left, the symbol “R” the right, the symbol “U” the upper, and the symbol “D” the lower. In addition, the symbols “HL-HR” represent a horizontal line seen in front from the driver-side (i.e., driver's view), and the symbols “HR-HL” represent a horizontal line seen as the automobile- or the headlamp-side is viewed from the front (so-called front view or plane view). The symbols “VU-VD” represent a vertical line. Further, as employed both in the appended claims and in the present specification document, the terms “front,” “back,” “left,” “right,” “upper,” and “lower” each has the same meaning.
b) Description of the Prior Art
Automotive headlamps in which a prescribed low beam distribution pattern and high beam distribution pattern each can be obtained by entire-surface reflection light distribution control of the reflecting surface of its reflector include, for example, those described in Japanese Patent Laid-Open Publication No. Hei 8-329703.
Hereinafter, the outline of such an automotive headlamp will be described with reference to
FIGS. 1 through 3
. Note that the automotive headlamp illustrated is to be mounted on the left side of an automobile for right traffic. An automotive headlamp to be mounted on an automobile for left traffic is the reverse of this illustrated automotive headlamp in the horizontal arrangement of a reflecting surface
40
, a high-beam filament
52
, and the like. Moreover, an automotive headlamp to be mounted on the right side of an automobile, while identical to this illustrated automotive headlamp in the arrangement of the reflecting surface
40
, the high-beam filament
52
, and the like, replaces its lamp housing
1
, lens
2
, and reflector
4
with those generally symmetrical in shape.
This automotive headlamp has a lamp chamber
3
defined by the lamp housing
1
and the lens (outer lens)
2
. In this lamp chamber
3
, the reflector
4
separately formed from the lamp housing
1
is arranged to be rotatable in vertical and horizontal directions, by a pivot mechanism (not shown), an optical axis adjustment mechanism (not shown), and the like. This reflector
4
has a reflecting surface
40
constituted by a complex reflecting surface. This reflecting surface
40
, i.e. the complex reflecting surface, comprises reflecting surface segments (not shown) sectioned in a plurality of pieces all around, and is referred to as so-called free-form curved surface. This complex reflecting surface, as described in Japanese Patent Laid-Open Publication No. Hei 9-306220. for example, includes that divided into a large number of blocks, that divided into a small number of blocks, and that having a plurality of blocks continuously connected with one another (the connecting lines therebetween not being visible).
In the strict sense, this complex reflecting surface has more than one single focus. The plurality of paraboloids of revolution constituting the complex reflecting surface, however, differ in focal length from each other but merely slightly, and practically share the same focus. Thus, the focus will be referred to as focus F in the present specification document, while the focus F shown in the drawings is a pseudo focus in the strict sense. Similarly, while the optical axis Z-Z (also referred to as reference axis Z-Z) shown in the drawings is a pseudo optical axis in the strict sense, it will be referred to as optical axis in the present specification document.
To the above-described reflector
4
is detachably attached a light source bulb
5
. This light source bulb
5
is a light source bulb with no shading hood, in which a low-beam (dipped-beam) filament
51
and a high-beam (main-beam) filament
52
are arranged in a glass envelope
50
, and this glass envelope is provided with, e.g., coating
54
of black paint (for intercepting direct lights from the low-beam filament
51
and high-beam filament
52
to the lens
2
) at an extremity thereof.
The low-beam filament
51
mentioned above forms a generally cylindrical shape of coil structure, and is generally parallel to the optical axis Z-Z. This filament
51
is positioned forward of the focus F. The high-beam filament
52
also forms a generally cylindrical shape of coil structure, and is generally parallel to the optical axis Z-Z. This filament
52
is positioned in the vicinity of the focus F and obliquely below the low-beam filament
51
(at the lower rightward as shown in
FIG. 11A
, for the right-traffic; at the lower leftward as shown in
FIG. 6C
, for the left-traffic). The central axis of the low-beam filament
51
described above generally coincides with the aforementioned optical axis Z-Z (reference axis Z-Z), and lies below the central axis of the aforementioned glass envelope
50
, i.e., below the envelope axis Z′-Z′. The reason why the central axis Z-Z of this low-beam filament
51
is positioned below the envelope axis Z′-Z′ is to obtain a stable light-shade boundary line
71
(so-called cut line) in the low-beam distribution pattern shown in
FIG. 4
to be described later. That is, as previously known, the central axis Z-Z of the low-beam filament
51
is shifted to downward of the envelope axis Z′-Z′ to prevent the converged image (virtual image) of the reflected light in the inner peripheral portion of the glass envelope
50
from appearing above the light-shade boundary line
71
of the low beam distribution pattern LP.
In the drawings, reference numeral
6
designates a shade. This shade
6
is fixed to the aforesaid reflectors
4
and covers the front of the aforesaid light source bulb
5
, so as to intercept the direct lights from the low-beam filament
51
and the high-beam filament
52
to the invalid portions
42
(portions with no direct involvement to the light distribution of the headlamp) of the reflector
4
and to the lens
2
. In addition, reference numeral
60
designates a rubber cap. This rubber cap
60
is watertightly and detachably attached to between the base of the light source bulb
5
and the rear opening portion of the lamp housing
1
via an attaching cap
61
, thereby maintaining the interior of the lamp chamber
3
watertight.
Now, when in the automotive headlamp described above the low-beam filament
51
is lit, lights from this low-beam filament
51
are reflected over the entire surface of the reflecting surface
40
of the reflector
4
, and the reflected lights are irradiated out through the lens
2
with the prescribed low beam distribution pattern LP shown in FIG.
4
. When in contrast the high-beam filament
52
is lit, lights from this high-beam filament
52
are reflected over the entire surface of the reflecting surface
40
, and the reflected lights are irradiated out through the lens
2
with a prescribed high beam distribution pattern HP shown in FIG.
5
.
In this way, the prescribed low beam distribution pattern LP and the prescribed high beam distribution pattern HP each is formed by the entire-surface reflection light distribution control of the reflecting surface
40
of the reflector
4
.
The prescribed low beam distribution pattern LP and prescribed high beam distribution pattern HP mentioned above designa
Foley & Lardner
Ichikoh Industries Ltd.
Patel Ashok
Zimmerman Glenn
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