Electric lamp and discharge devices – With optical device or special ray transmissive envelope – Reflector
Reexamination Certificate
1999-01-26
2002-04-09
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
With optical device or special ray transmissive envelope
Reflector
C313S114000, C313S116000, C362S346000, C362S347000, C362S297000
Reexamination Certificate
active
06369492
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a lighting unit with a reflecting mirror used for lighting up goods at stores or the like, i.e., a lighting unit having a bulb with a reflecting mirror.
BACKGROUND OF THE INVENTION
A conventional lighting unit with a dichroic reflecting mirror is disclosed in U.S. Pat. No. 5,272,408. The lighting unit is produced by combining a funnel-shaped reflecting mirror which has a reflecting mirror surface provided with a dichroic film, as a light interference film and a bulb, such as a tungsten halogen lamp. Such lighting units with dichroic reflecting mirrors are used for lighting goods at stores or the like. As shown in
FIG. 4
, such a lighting unit with a reflecting mirror includes a funnel-shaped reflecting mirror
23
having a reflecting part
25
and a neck portion
26
, and, as a light source, a bulb, such as a straight tungsten halogen lamp
21
, provided inside the reflecting mirror
23
. A tungsten filament
30
is provided within the tungsten halogen lamp
23
. The reflecting part
25
has a reflecting surface provided with a dichroic film
24
, while the neck portion
26
is connected with the reflecting part
23
. The tungsten halogen lamp
21
is inserted and sealed into a base
28
at the upper position.
The tungsten halogen lamp
21
is substantially coaxially located inside the reflecting mirror
23
. The neck portion
26
of the reflecting mirror
23
and the sealing portion
22
of the tungsten halogen lamp
21
are inserted into the base
28
and combined into one component by injecting an inorganic adhesive
29
into the base
28
.
In the conventional lighting unit with a reflecting mirror, it is desired that as much of the light and dark image of the coiled tungsten filament
30
contained in the tungsten halogen lamp
21
as possible is prevented from being seen on the irradiated surface during lighting, so that the illuminance of the irradiated surface will be uniform and any irradiation nonuniformity on the irradiated surface can be avoided. For this purpose, fine reflecting surfaces
25
a
(
FIG. 5
) are formed on the reflecting surface of the reflecting part
25
in order to scatter the reflected light appropriately. More specifically, hexagonal fine reflecting surfaces
25
a
are radially arrayed in good order without leaving clearance, and the fine reflecting surfaces become smaller gradually from the opening part
27
of the reflecting mirror
23
toward the neck portion
26
.
In the conventional tungsten halogen lamp with a reflecting mirror, hexagonal fine reflecting surfaces
25
a
are formed without clearance. As a result, concave or convex boundary lines
25
b
are formed at the borders of adjacent fine reflecting surfaces
25
a
in radial lines from the opening part
27
of the reflecting mirror
23
to the neck portion
26
. Light that falls on the boundary will not be scattered, and thus, irradiation nonuniformity, such as radial lines, occurs on the irradiated surface.
As shown in
FIG. 6
, the luminous intensity distribution of the conventional tungsten halogen lamp with a reflecting mirror has irregularities in the curve before the light intensity comes to the peak. The irregularities indicate the radial linear difference between the bright parts and dark parts, which causes nonuniformity in irradiation.
SUMMARY OF THE INVENTION
In order to solve the problems of the conventional units, this invention aims to provide a lighting unit with a reflecting mirror that can prevent irradiation nonuniformity on the irradiated surface.
To achieve the aims, a lighting unit with a reflecting mirror of this invention includes a bulb as a light source, arranged inside a funnel-shaped reflecting mirror having a reflecting surface, and a plurality of fine reflecting planes that are arranged on the reflecting surface non-centrally originating and non-radially without clearance.
It is preferable in the lighting unit with a reflecting mirror that the shapes of the fine reflecting surfaces are at least one shape selected from the group consisting of a circle, an ellipse, and a polygon.
It is preferable in the lighting unit with a reflecting mirror that the fine reflecting surfaces are concave or convex.
It is also preferable in the lighting unit with a reflecting mirror that the surface of each fine reflecting surface is dented or protruded in the range of 0.01 to 1.0 mm.
It is also preferable in the lighting unit with a reflecting mirror that a dichroic film is provided on at least one wall surface of the reflecting mirror. Here, a dichroic film refers to a light interference film formed by alternately laminating a high-refractive layer including zinc sulphide (ZnS) and a low-refractive layer including magnesium fluoride. The film radiates a visible light emitted from the light source on the front surface of the mirror, and selectively lets an infrared ray go to the back of the mirror.
It is also preferable in the lighting unit with a reflecting mirror that the size of the fine reflecting surfaces on the entire reflecting surface is not varied substantially. The term ‘not varied substantially’ means that slight differences due to manufacturing processes is permissible.
It is also preferable in the lighting unit with a reflecting mirror that the luminous intensity curve is smooth when the beam angle just beneath the light source is 0° and the beam angle at the neck portion of the same light source is 90°. When the curve of the luminous intensity distribution is smooth before it comes to a peak and has no irregularities, the brightness is not varied in radial lines and there is no irradiation nonuniformity.
It is also preferable in the lighting unit with a reflecting mirror that the appearance of the fine reflecting surfaces is a honeycomb, so that the fine reflecting surfaces can be formed without clearance.
It is also preferable in the lighting unit with a reflecting mirror that the size of the fine reflecting surfaces ranges from 0.01 to 5 mm long, and from 0.01 to 5 mm wide.
It is also preferable in the lighting unit with a reflecting mirror that the bulb as a light source is at least one selected from the group consisting of a tungsten halogen lamp and a discharge lamp.
REFERENCES:
patent: 1590130 (1926-06-01), Sturgeon, Jr.
patent: 4864476 (1989-09-01), Lemons et al.
patent: 5144190 (1992-09-01), Thomas et al.
patent: 5272408 (1993-12-01), Levin et al.
patent: 5442252 (1995-08-01), Golz
patent: 5483424 (1996-01-01), Lightbody
patent: 5568967 (1996-10-01), Sikkens et al.
patent: 6086224 (2000-06-01), Sugimoto
patent: 6086227 (2000-07-01), O'Connell et al.
patent: 6102555 (2000-08-01), Mizoguchi
patent: 0 136 684 (1985-04-01), None
patent: 0 250 191 (1987-12-01), None
patent: 05021043 (1993-01-01), None
European Search Report dated Mar. 6, 2001, 4 pages.
Matsushita Electronics Corporation
Patel Nimeshkumar D.
Rosenthal & Osha L.L.P.
Santiago Mariceli
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