Illumination – Supported by vehicle structure – Plural light sources
Reexamination Certificate
2002-09-17
2004-10-19
Husar, Stephen F (Department: 2875)
Illumination
Supported by vehicle structure
Plural light sources
C362S518000, C362S520000, C362S245000, C362S308000, C362S328000
Reexamination Certificate
active
06805476
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX
Not applicable
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular lamp employing a plurality of LED light sources and, more particularly, to a vehicular lamp which radiates light using an indirect illumination technique.
Many vehicular lamps that have been employed in recent years are equipped with LED light sources. For example, Japanese Patent Application Laid-Open No. 11-306810 discloses a lamp having LED light sources disposed so as to be invisible from the front of the lamp, thus providing a soft lighting effect due to the use of an indirect illumination technique. Further, as disclosed in German Patent Application Laid-Open No. 19638081, some vehicular lamps of an indirect illumination type are equipped with Fresnel lenses as well as LED light sources.
FIG. 9
is a front view of a vehicular lamp
100
of such a type. As shown in the drawing, in the vehicular lamp
100
light emitted by a plurality of LED light sources
102
disposed facing upward is formed into parallel light beams by a plurality of Fresnel lenses
104
disposed above the LED light sources
102
, and a reflector
106
reflects the parallel light beams from the Fresnel lenses
104
in the directly forward direction of the lamp. The light emitted by the light sources thus can be effectively utilized by combining the LED light sources
102
with the Fresnel lenses
104
.
The reflector
106
of the vehicular lamp
100
is divided into smaller sub reflectors
108
disposed in the areas where the parallel light beams from the Fresnel lenses
104
impinge, and the sub reflectors
108
are made different in height so as to conform to the contour of the lamp. In order to ensure that the parallel light beams from each of the Fresnel lenses
104
impinges on a reflecting surface
108
a
of a corresponding one of the sub reflectors
108
, the sub reflectors
108
are designed such that the angle of inclination in the directly forward direction of the lamp increases as the height of the sub reflectors
108
decreases.
However, the aforementioned conventional vehicular lamp
100
lacks a desired visual impressiveness when lighted.
That is, as shown in
FIG. 10
, the vehicular lamp
100
is designed such that the sub reflectors
108
and the Fresnel lenses
104
are all equal in lateral width (P1′=P2′=P3′=P4′=P5′). The LED light sources
102
are all spaced from corresponding ones of the Fresnel lenses
104
by an equal distance H′. Thus, the luminous fluxes impinging on each of the Fresnel lenses
104
from corresponding ones of the LED light sources
102
have equal intensities (F
1
′=F
2
′=F
3
′=F
4
′=F
5
′). On the other hand, since the sub reflectors
108
differ in projected area in the forward direction of the lamp (A
1
′<A
2
′<A
3
′<A
4
′<A
5
′), the reflecting surfaces
108
a
of the sub reflectors
108
increase in luminance and appear brighter as the aforementioned projected areas become smaller in size.
More specifically, the reflecting surface
108
a
of each of the sub reflectors
108
is vertically divided into a plurality of segments so as to form the sub reflector in a stepped manner. Each segment contains a reflecting element
108
s
for diffusively reflecting the parallel light flux from a corresponding one of the Fresnel lenses
104
in the directly forward direction of the lamp and a vertically extending step portion
108
r
. Hence, if the reflector
106
is observed from the front of the lamp when the lamp is lighted, central portions of the reflecting elements
108
s
appear bright as glitter portions B′.
The glitter portions B′ appear substantially equally bright among the reflecting elements
108
s
and among the sub reflectors
108
. However, the vertical distance among the reflecting elements
108
s
constituting each of the sub reflectors
108
decreases in proportion to a decrease in the aforementioned projected area. Hence, if the sub reflectors
108
are observed one by one, they increase in luminance and look brighter in proportion to the decrease in the aforementioned projected area.
Hence, it is impossible to make the entire reflecting surface of the reflector
106
look substantially homogeneous in brightness, which adversely affects the appearance of the lamp when the lamp is lighted.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made in consideration of such circumstances. It is an object of the present invention to provide a vehicular lamp that radiates light emitted from a plurality of LED light sources through indirect illumination and which has an improved appearance when lighted.
The present invention achieves the above and other objects with a vehicular lamp having a controlled positional relationship between each of LED light sources and corresponding ones of the lenses.
More specifically, a vehicular lamp according to the present invention comprises a plurality of LED light sources, a plurality of lenses for forming parallel light beams from the light from the LED light sources, a reflector for reflecting the parallel light beams from the lenses in the directly forward direction of the lamp, and a translucent cover disposed in front of the reflector with respect to the lamp. The lenses are disposed such that the parallel light beams travel in the same direction, the reflector is divided into sub reflectors according to areas on which the parallel light beams from the lenses impinge, the sub reflectors differ in length with respect to the direction of radiation of the parallel light beams and are designed such that the angle of inclination in the directly forward direction of the lamp increases in proportion to the decrease in the length of the sub reflectors in the direction of radiation of the parallel light beams, and the distance between each of the LED light sources and the corresponding one of the lenses increases in proportion to the decrease in the length of the sub reflector in the direction of radiation of the parallel light beams.
The lenses are not specifically limited in construction as long as they can form parallel light beams from the light emitted by the LED light sources. For instance, single spherical lenses, combinational lenses, Fresnel lenses, and the like can be adopted.
Also, the directions of the parallel light beams are not specifically limited as long as they intersect the longitudinal direction of the lamp. For instance, the parallel light beams can be directed upward or transversely while being perpendicular to the longitudinal direction of the lamp.
The reflector may be integrally formed of a plurality of sub reflectors or be formed of separated sub reflectors.
The sub reflectors are not specifically limited in shape, size, or the like as long as they differ in length with respect to the direction of radiation of the parallel light beams and as long as they are designed such that the angle of inclination in the directly forward direction of the lamp increases in proportion to the decrease in the length in the direction of radiation of the parallel light beams. It is not absolutely required that all the sub reflectors are different in length with respect to the direction of radiation of the parallel light beams. It is appropriate that at least two of the sub reflectors be different in length with respect to the direction of radiation of the parallel light beams.
As is apparent from the description above, the vehicular lamp according to the present invention is designed such that the lenses for forming parallel light beams from light from the LED light sources are disposed so as to direct the parallel light beams in the same direction, the reflector for reflecting the parallel light beams from the lenses in the dire
Husar Stephen F
Koito Manufacturing Co. Ltd.
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