Illumination – Light source and modifier – Including reflector
Reexamination Certificate
1999-04-30
2001-06-12
O'Shea, Sandra (Department: 2875)
Illumination
Light source and modifier
Including reflector
C362S297000, C362S346000, C362S518000, C362S516000, C362S348000, C362S309000, C362S308000, C362S328000, C362S268000, C362S351000, C362S307000, C362S343000
Reexamination Certificate
active
06244731
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to lamps and, more particularly, to a lamp suitable for use as an illumination lamp for a vehicle such as a head lamp or fog lamp, a signal lamp for a vehicle such as a tail lamp or turn signal lamp, a signal lamp for road traffic, or a signal lamp for railway traffic.
2. Background Art
FIGS. 1
to
3
show conventional lamps of this type. A lamp
90
shown in
FIG. 1
basically includes: a light source
91
; a revolutional paraboloidal reflector
92
; and a lens
93
with a lens cut
93
a.
A light beam from the light source
91
is reflected by the revolutional paraboloidal reflector
92
to form a parallel light beam. The reflected light beam is diffused properly by the lens cut
93
a
of the lens
93
to provide a desired light distribution property.
A lamp
80
shown in
FIG. 2
includes: a light source
81
; a reflector composed of a composite reflecting surface
82
; and a lens
83
. The composite reflecting surface
82
has a plurality of cylindrical parabolic reflecting surfaces that are arranged to have a parabolic configuration in a vertical cross section taken when the lamp
80
is in a mounted state and have a linear configuration in a horizontal cross section (the state shown in the drawing). The lens
83
has no lens cut so that it is see-through. In the lamp
80
, the composite reflecting surface
82
provides the light distribution property by itself.
A lamp
70
shown in
FIG. 3
includes: a light source
71
; a reflector composed of an ellipsoidal reflecting surface
72
having the light source
71
disposed at a first focal point; an aspheric lens
73
; and a shade
74
provided if necessary. The ellipsoidal reflecting surface is composed of a spheroid, a composite ellipsoidal surface, or an ellipsoidal free-form surface. In the arrangement, the aspheric lens
73
projects, under magnification, a light source image formed by converging a light beam at a second focal point to provide an irradiating light beam. The lamp
70
of the type using the ellipsoidal reflecting surface
72
is termed a projector type lamp. The light distribution property is obtained by covering an unwanted portion with the shade
74
.
In the lamp
90
shown in
FIG. 1
, however, the lens cut
93
a
should be formed to have high optical intensity, so that a significant variation is produced in the thickness of the lens
93
. This degrades the transparency of the lens and makes it impossible to provide an appearance with enhanced clarity and sense of depth, which is currently preferred on the market.
It is possible to impart an appearance with enhanced clarity to the lamp
80
shown in
FIG. 2
, since the lens
83
without a lens cut is see-through. However, since the composite reflecting surface
82
positioned at a recessed portion forms a light distribution property, the formation of the light distribution property is limited by such a factor as difficulty in determining the light distribution property in the direction of width.
The lamp
70
shown in
FIG. 3
is difficult to mount because of its increased depth dimension. Moreover, the aspheric lens
73
having a small outer diameter leads to a reduced light-emitting area. Therefore, the lamp
70
used as a head lamp is inferior in visibility when viewed from an oncoming vehicle.
Each of the conventional lamps
70
,
80
, and
90
with the aforesaid structures is generally in wide use. Hence, it is impossible to distinguish them from other items and achieve novelty in terms of design. Furthermore, since the coefficient of use of a luminous flux from the light source is dependent on the depth dimension, the coefficient of use is lowered if the lamp is reduced in thickness.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a lamp with an unprecedented and novel design including a plurality of aspheric lenses.
Another object of the present invention is to provide a lamp having a light distribution property free from constraints and exhibiting enhanced flexibility particularly in the horizontal direction.
Still another object of the present invention is to provide a lamp having a desired light-emitting area and improved visibility when viewed from an oncoming vehicle.
Yet another object of the present invention is to provide a lamp wherein the coefficient of use of a luminous flux from the light source is unaffected by the depth dimension.
One aspect of the present invention is to provide a lamp comprising: a light source; a composite reflector including a plurality of first reflecting surface units and a plurality of second reflecting surface units, of which the identical reflecting surface units are combined concentrically to compose the composite reflector, each of the first reflecting surface units being formed of a first reflecting surface configuration obtained by cutting, radially around a center axis of the light source, a portion from a spheroid having a first focal point located on the center axis and adjacent the light source and a second focal point located on a line passing through the first focal point and tilted appropriately from the center axis such that the cut portion spans a range of 15° to 90° around the center axis, each of the second reflecting surface units being composed of a second reflecting surface configuration obtained by cutting, radially around the center axis, a portion from a spheroid having the first focal point and a second focal point located external to the first reflecting surface configuration such that the cut portion spans a range of 15° to 90° around the center axis, the first and second reflecting surface configurations being defined in non-overlapping relation with each other such that a reflected light beam converged at each of the second focal points is effective as an irradiating light beam from the lamp; and aspheric lenses provided to correspond to the respective second focal points of the reflecting surface units of the composite reflector and converge reflected light beams from the respective reflecting surface units.
If necessary, the composite reflector may further include a plurality of third reflecting surface units combined concentrically to compose the composite reflector, each of the third reflecting surface units being formed of a third reflecting surface configuration obtained by cutting, radially around the center axis, a portion from a spheroid having the first focal point and a second focal point located external to the second reflecting surface configuration such that the cut portion spans a range of 15° to 90° around the center axis, the third reflecting surface configuration being defined in non-overlapping relation with the other reflecting surface configurations such that a reflected light beam converged at the second focal point is effective as an irradiating light beam from the lamp. In this case, the lamp may further comprise aspheric lenses provided to correspond to the respective second focal points of the reflecting surface units and converge reflected light beams from the respective reflecting surface units.
Shades for forming a light distribution pattern may be disposed at respective near-focal points of the aspheric lenses.
In the lamp, a central reflector obtained by cutting a portion from a spheroid having a first focal point adjacent the light source for causing the center axis to coincide with a long axis and an aspheric lens located to correspond to a second focal point of the central reflector may also be disposed on the center axis.
In this case, a shade for forming a light distribution pattern may be disposed at a near-focal point of the aspheric lens disposed to correspond to the central reflector.
Another aspect of the present invention is to provide a lamp comprising: a light source; a composite reflector including a plurality of first reflecting surface units and a plurality of second reflecting surface units, of which the identical surface reflecting surface units are combined concentrically to form the composite reflector, eac
Futami Takashi
Kawaguchi Yoshifumi
Koiko Teruo
O'Shea Sandra
Ostrolenk Faber Gerb & Soffen, LLP
Stanley Electric Co. Ltd.
Ton Anabel M
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