Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
1999-12-09
2002-05-14
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Light modifier
C362S517000, C362S518000, C362S516000, C362S521000, C362S348000, C362S308000, C362S309000
Reexamination Certificate
active
06386743
ABSTRACT:
This invention claims the benefit of Japanese Patent Application No. 10-351622, filed on Dec. 10, 1998, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to configurations for a projection light used for illumination or signaling functions, and more particularly to configurations for vehicle lights such as a headlight, fog light, tail light, turn signal light, or traffic light for roadways and railroads. The projection light is generally circular in a front view and can include a light source, an ellipse group reflecting surface and a thick front lens. The projection light distribution is basically determined by the principles of the projection of a focused images. The projection light includes the following light ray path: light rays are emitted from the light source and reflected by the reflector, focused to at least one point, then projected to travel through the thick circular front lens. The ellipse group reflecting surface is defined by a reflecting surface that has a cross-section formed as an ellipse or similar shape such as a rotated parabolic surface, a complex elliptic surface, or an elliptical free-curved surface.
2. Discussion of the Related Art
FIGS. 15-17
illustrate configurations of conventional lights that can be used as a vehicle or traffic light. A conventional vehicle light
90
shown in
FIG. 15
includes a light source
91
, a rotated parabolic surface reflector
92
having a focus on the light source
91
, and a front lens
93
having prismatic cuts
93
a
on its inner surface.
Light emitted from the light source
91
is reflected by the rotated parabolic surface reflector
92
to form parallel light rays. The reflected light is then diffused by the prismatic cuts
93
a
when passing through the front lens
93
, thereby providing a predetermined light distribution.
FIG. 16
illustrates a horizontal cross sectional assembled view of another conventional vehicle light
80
. The conventional vehicle light
80
includes a light source
81
, a complex reflecting surface
82
, and a front lens
83
that has no prismatic cuts. The complex reflecting surface
82
can be parabolic with a focus located at the light source
81
in a vertical cross sectional assembled view, and configured as a complex paraboloidal solid surface composed of connected straight lines in a horizontal cross sectional assembled view. Light distribution patterns for the light
80
are formed by adjusting the complex reflecting surface
82
.
FIG. 17
illustrates a conventional projection-type vehicle light
70
including a light source
71
, an aspherical lens
73
, an elliptical reflecting surface
72
having a first focus on the light source
71
and a second focus at which light reflected from the elliptical reflecting surface
72
converges. The focused image of light rays is enlarged and projected to the aspherical lens
73
. The light rays are refracted by the aspherical lens
73
to create specific light distribution patterns for the projection-type vehicle light
70
.
A shade
74
may be used to prohibit unnecessary light rays, e.g., high beam type light rays, from passing through the aspherical lens
73
. The shade
74
includes a top portion located around the second focus of the elliptical reflecting surface
72
.
Improvements to multi projection lens type projection lights are also disclosed in Japanese Patent Publication No. HEI 03-64962.
The conventional vehicle and traffic lights described above have the following problems. The vehicle light
90
in
FIG. 15
does not have a substantially transparent front lens
93
and therefore cannot provide a three dimensional feeling. These features are becoming important requirements in the market. The prismatic cuts
93
a
must have optical function, requiring deep straight line cuts or curved line cuts having great curvature. Accordingly, the lens
93
is relatively thick, and the transparency of the lens
93
is deteriorated.
The vehicle light
80
in
FIG. 16
has superior transparency because the lens
83
does not have any prismatic cuts. However, it is difficult to adjust the complex reflecting surface
82
and therefore is also difficult to obtain a sufficiently wide light distribution pattern. The light distribution patterns of the vehicle light
80
are determined by adjusting the entire combined complex reflecting surface
82
. Adjustment cannot be easily achieved by manipulation of discrete portions of the complex reflecting surface
82
.
The projecting-type vehicle light
70
in
FIG. 17
is very long and deep and is difficult to design and/or place into a vehicle body. In addition, the external diameter of the aspherical lens
73
is small, and thus the light emitting area of the projection-type vehicle light
70
is small. When the projection-type vehicle light
70
is used as a headlight, visibility of a vehicle incorporating the projection-type vehicle light
70
is reduced as viewed from another vehicle traveling in an oncoming lane.
The vehicle lights
70
,
80
,
90
are commonly used in the market but lack design uniqueness and do not provide a novel appearance. Furthermore, none of the vehicle lights
70
,
80
,
90
provides sufficient efficiency when the depth of the light is reduced because efficiency of lumen output of a light source depends on the depth of the vehicle light.
The vehicle lamp disclosed in Japanese Patent Publication No. HEI 03-64962 has the following problems. Since optical axes of the respective aspherical lenses are aligned in different directions from each other, light distribution patterns of the vehicle lamp are formed by a combination of the light distributions from the aspherical lenses. Therefore, there is a tendency for the connecting lines of respective light distribution patterns for each aspherical lens to clearly appear in the light distribution pattern of the vehicle lamp. The light distribution patterns of this projection-type vehicle light is often thought of as not thoroughly uniform. Furthermore, utilization efficiency of reflected light by the elliptical reflecting surface is small. The second focus of the elliptical reflecting surface and the focus of aspherical lens is a common point. The radius of curvature of the aspherical lens is not the same as the radius of curvature of the ellipse. The aspherical lens is not located in a position in which the imaginary hemispherical portion which is a mirror of the elliptical reflecting surface is located. Therefore, a considerable amount of the light rays that are reflected by the elliptical reflecting surface are not incident to the aspherical lens, especially light rays that are reflected by the substantially lower half portion of the elliptical reflecting surface. Although the elliptical reflecting surface extends towards the aspherical lens without changing the diameter of the aspherical lens
4
, the amount of light incident on the aspherical lens
73
does not substantially improve. Light rays reflected by the extended reflecting portion are not incident to the aspherical lens
73
because the focus of the aspherical lens
73
is a point. Additionally, light rays reflected by the lower half portion of the reflector from the light source are not incident to the aspherical lens
73
if the optical axes of the reflector and the aspherical lens are parallel to each other, because the light rays reflected by the lower half portion become upwardly directed light rays which are not necessary for the formation of the passing-by low beam light distribution pattern. To obtain a larger amount of light, the overall size of the projection-type vehicle light must be enlarged.
SUMMARY OF THE INVENTION
The invention is directed to a projection-type vehicle headlight or traffic light that substantially obviates one or more of the above problems due to the limitations and disadvantages of the related art.
An object of the invention is to provide a projection-type vehicle light that has a novel appearance with superior transparency of he front lens and which provides a three
Futami Takashi
Koike Teruo
Morgan & Lewis & Bockius, LLP
O'Shea Sandra
Stanley Electric Corporation
Ton Anabel
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