Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
1998-08-20
2001-05-01
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Light modifier
C362S346000, C362S348000, C362S517000, C362S297000
Reexamination Certificate
active
06224246
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a signal lamp for vehicles, the reflective surface of which is composed of a plurality of reflecting elements. More particularly, the present invention relates to a structure of a reflective surface which improves in external appearance.
2. Related Art
As shown in
FIGS. 12
to
14
, a conventional signal lamp for vehicles is generally provided with a light source bulb
2
, a reflector
4
having a reflective surface
4
a
for reflecting light forward sent from the light source bulb
2
and a lens
6
arranged in the front of the reflector
4
.
Recently, many of signal lamps for vehicle are composed as follows. As shown in each drawing, the reflective surface
4
a
is composed of a plurality of diffusing reflection elements
4
s
, so that the burden imposed on the light diffusing function of lens steps
6
s
formed on the inner surface of the lens
6
can be reduced. Due to the foregoing, it becomes possible to ensure a feeling of transparency and depth of the lighting device.
However, the following problems may be encountered in the conventional signal lamp for vehicles described above. When the lighting device is viewed from the front side under the condition that the light source bulb
2
is turned on, brightness of the reflecting light, which has been reflected in a portion on the reflective surface
4
a
, greatly changes depending upon the portion. Due to the foregoing, the lighting device looks unattractive when viewed from the outside.
The above problem will be explained in detail as follows. For example, as shown in
FIGS. 13 and 14
, when each diffusing reflection element
4
s
has a light diffusing function in the transverse direction, and on the other hand when it has no light diffusing function in the vertical direction, only light reflected in the central region of the light diffusing reflection element
4
s
in the transverse direction is sent to the direction of the optical axis Ax of the reflector. Therefore, when the lighting device is observed from the front side under the condition that the light source bulb
2
is turned on, the rectangular central region
4
s
1
of each light diffusing reflection element
4
s
in the transverse direction, that is, the optical axis direction reflecting region is seen as a belt-shaped bright portion B, the brightness of which is high as shown in FIG.
15
. However, luminance of this bright portion B is different from each other according to the position at which the diffusing reflection element
4
s
is arranged as shown by the mesh in the drawing.
That is, in the light diffusing reflection element
4
s
distant from the filament
2
a
(light source) of the light source bulb
2
, illuminance of the incident light emitting from the filament
2
a
becomes low. Therefore, luminance of the bright portion B of the light diffusing reflection element
4
s
also becomes low. In the case of a linear light source such as the filament
2
a
described above, the light distribution characteristics (spatial distribution of luminous intensity) are described as follows as shown in FIGS.
16
(
a
) and
16
(
b
). Luminous intensity in a direction close to the central axis Axf of the filament
2
a
is lower than luminous intensity in a direction perpendicular to the central axis Axf.
Therefore, in the case where the filament
2
a
extends in the perpendicular direction as shown in
FIG. 15
, even if the distance from the filament
2
a
is the same, illuminance of the diffusing reflection element
4
s
located in the upper or lower position of the optical axis Ax is lower than illuminance of the diffusing reflection element
4
s
located on the side of the optical axis Ax when light emitting from the filament
2
a
is incident. For the above reasons, when the entire reflective surface
4
a
is observed, a portion close to the side of the optical axis Ax is very bright, however, a peripheral portion is very dark, that is, brightness of the entire reflective surface
4
a
is not uniform. Due to the foregoing, the lighting device looks unattractive.
SUMMARY OF THE INVENTION
The present invention was accomplished to solve the foregoing problems accompanying the conventional signal lamp for vehicles. An object of the present invention is to provide a signal lamp for vehicles, the external appearance of which can be improved in the case of turning on the light source bulb.
According to the present invention, light emitted from a light source is incident on reflecting elements of the lamp reflector, where the reflecting elements are different distances from the light source, and the higher the illuminance of a reflecting element, caused by the incident light, the lower the area ratio of the region of the element causing reflection in the optical axis direction is set to be.
The above and other objects can be accomplished by a provision of a signal lamp for vehicles which, according to the present invention, includes: a light source; a reflector having a reflective surface for reflecting light forward emitting from the light source, the reflective surface being composed of a plurality of diffusing reflection elements each comprising a reflecting region which reflects light emitting from the light source in the optical axis direction, the area ratio of the reflection region, where the illuminance of the reflecting element with respect to the incident light emitting from the light source is high, being lower than the others where the illuminance of which is low; and a lens arranged in the front of the reflector.
The diffusing reflection element may be an element in which light is diffused and reflected only in one direction. Alternatively, the diffusing reflection element may be an element in which light is diffused and reflected in two directions. An external shape and a surface shape of the above diffusing reflection element are not particularly limited to a specific embodiment.
Concerning the illuminance of the incident light emitting from the light source, as long as it can be measured by the same reference for each diffusing reflection element, the value of illuminance is not particularly limited. For example, it is possible to adopt the mean value of illuminance at each point of the diffusing reflection element, illuminance of the center of the diffusing reflection element, and illuminance of the point of the diffusing reflection element located closest to the optical axis.
As shown in the arrangement described above, the reflective surface of the reflector of the signal lamp for vehicles of the present invention is composed of a plurality of diffusing reflection elements. According to the present invention, the higher the illuminance of a reflecting element with respect to the incident light emitting from the light source is, the lower the area ratio of the optical axis direction reflecting region is set to be. Therefore, the following action effects can be provided.
When the lighting device is observed from the front side under the condition that the light source is turned on, the optical axis direction reflecting region of each diffusing reflection element is bright because it becomes a bright portion. However, illuminance of the incident light emitting from the light source is different according to a distance from the light source to the diffusing reflection element, and also according to a shape and arrangement of the light source. Therefore, luminance of the above bright portion is generally different between the diffusing reflection elements.
In the present invention, the higher the illuminance of a reflecting element with respect to the incident light emitting from the light source is, the lower the area ratio of the optical axis direction reflecting region is set to be. Therefore, although luminance itself of the above bright portion is not changed, an area of the bright portion is reduced in inverse proportion to the luminance. Due to the foregoing, even when luminance of the bright portion is different between the diffusing reflection elements, the l
Natsume Kazunori
Satsukawa Hideaki
Koito Manufacturing Co. Ltd.
O'Shea Sandra
Sughrue Mion Zinn Macpeak & Seas, PLLC
Ton Anabel M.
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