Electric lamp and discharge devices: systems – Combined load device or load device temperature modifying... – Plural circuit elements
Reexamination Certificate
1999-12-03
2001-10-09
Vu, David (Department: 2821)
Electric lamp and discharge devices: systems
Combined load device or load device temperature modifying...
Plural circuit elements
C315S058000, C315S071000, C313S113000, C313S491000, C313S493000
Reexamination Certificate
active
06300716
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a high-intensity discharge lamp which is provided with a discharge lamp enclosure made of light-transmissive ceramics, a high-intensity discharge lamp utilizing the high-intensity discharge lamp, a lighting circuit for the high-intensity discharge lamp, and a lighting device.
BACKGROUND OF THE INVENTION
Recently, a high-intensity discharge lamp provided with a light-transmissive ceramic enclosure which is more profitable in its life-expectancy and lighting efficiency than a conventional discharge lamp silica glass enclosure.
FIG. 30
is a partial enlarged front section showing a sealing portion of a high-discharge lamp provided with a conventional light-transmissive ceramic enclosure.
FIG. 31
is another partial enlarged front section showing a sealing portion of a conventional high-discharge lamp.
In
FIGS. 30 and 31
, the numeral
101
denotes a small diameter cylinder portion. Also, the numeral
102
denotes a feed-conductor, and the numeral
103
denotes a sealant.
The small diameter cylinder portion
101
is coupled to one end of an envelope (not shown) defined in the center of a discharge lamp light-transmissive ceramic enclosure. While the small diameter cylinder portions
101
is defined a through-holes
101
a
which communicates to the envelope.
The feed-conductor
102
is provided with a sealable portion
102
a
and a refractory portion
102
b.
The sealable portion
102
a
is comprised of a sealable portion
102
a
1
which may be inserted in the small diameter cylinder portion
101
, and an outer protrusion
102
a
2
having a tip end to be coupled to the base end of the sealable portion
102
a
1
and a base end protruding outside the small diameter cylinder portion
101
.
The base end of the refractory portion
102
b
is coupled to the tip end of the sealable portion
102
a
made of the sealable metal. Further an electrode is mounted on the tip end of the refractory portion
102
b
(not shown). In order to couple the base end of the refractory portion
102
b
to the tip end of the sealable portion
102
a,
steps
102
a
3
and
102
b
1
are placed on, e.g., the tip end of the sealable portion
102
a
and the base end of the refractory portion
102
b
at their positions to be welded each other. The steps
102
a
3
and
102
b
1
are superimposed and then spot-welded each other up and down.
Further, the feed-conductor
102
is inserted into the small diameter cylinder portion
101
. Then a compound of a sealant
103
for sealing ceramics flows into the narrow gap between the small diameter cylinder portion
101
and a sealing portion
101
a
1
of the sealable portion
102
a
of the feed-conductor
102
inserted in the small diameter cylinder portion
101
and then solidified so that the small diameter cylinder portion
101
is sealed and the feed-conductor
102
is fixed to a predetermined position,
By the way, the outer protrusion
102
a
2
of the sealable portion
102
a
of the feed-conductor
102
protrudes outside and its tip end is coupled to the bane end of the sealable portion
102
a
1
. In a type of a outer bulb being housed in an exhausted outer bulb and lighting therein, the outer protrusion
102
a
may protrude outside the discharge lamp light-transmissive ceramic enclosure
101
and effect as an external lead-wire. However, in a type of a outer bulb exposing in air, the outer protrusion
102
a
must be sealed hermetically by the sealant so as not to be exposed in air for preventing from oxidation.
Accordingly, in the type of the outer bulb exposing in air, the outer protrusion
102
a
2
is coupled to an external lead-wire (now shown) made of an oxidation-resistant metal, and the junction is fit around by the ceramic washer (not shown), and sealed by a sealant with a melting point lower than that of the sealant
103
.
Further, for coupling the tip end of the outer protrusion
102
a
2
to the base end of the sealable portion
102
a
1
, steps
102
a
4
and
102
a
5
defined in the sealable portion
102
a
1
and the outer protrusion
102
a
2
are superimposed each other and then spot-welded.
To solve the problems in the prior art discharge lamp as described above, the inventors have developed a new high-intensity discharge lamp in which the sealable portion of the feed-conductor is formed by rounding a plate in a cylindrical shape with a junction line and filed the invention (hereinafter referred to prior invention) in Japan (Japanese Patent Application 10-257807). Accordingly the sealable portion becomes easy to be coupled to a refractory portion whose tip end being provided with an electrode. The sealable portion then becomes hard to be off-centered from the refractory portion.
FIG. 32
is a partial enlarged front section showing the prior invention of the high-intensity discharge lamp.
In
FIG. 32
, the same elements as those shown in
FIG. 31
are assigned with same marks.
The sealable portion
102
a
of the feed-conductor
102
is comprised of a cylindrical sealable portion
102
a
1
′ and an outer protrusion
102
a
2
.
The cylindrical sealable portion
102
a
1
′ is formed by cylindrically rounding a sealable metal plate. Thus the cylindrical sealable portion
102
a
1
′ has an axially extending junction line j which presents a narrow gap of about 1 to 10 &mgr;m in average.
The outer protrusion
102
a
2
is inserted into the cylindrical sealable portion
102
a
1
′. They are thus possible to be coupled each other by a shrinkage fitting at the sealing operation.
The refractory portion
102
b
is inserted into the cylindrical sealable portion
102
a
1
′, and then coupled thereto by a shrinkage fitting in the same way as that of the outer protrusion
102
a
2
.
By the way, the conventional arts have same drawbacks at the junction of the sealable portion and the refractory portion in the feed-conductor, and at the junction of a sealing and the outer protrusion in the sealable portion. That is, there are problems of that such a spot welding is troublesome and that those thus spot-welded are easy to be off. centered from each other.
The prior-art high-intensity discharge lamp is favorable in that it is easy to couple the sealable portion and the refractory portion and they are hardly off-centered from each other. However, when taken a configuration that the sealant fails to enter inside the cylindrical sealable portion
102
a
1
′, if it Leaks of the sealant occur at both the junction of the refractory portion and the cylindrical sealable portion
102
a
1
′ and the junction of the cylindrical sealable portion
102
a
1
′ and the outer protrusion
102
a
2
, the discharge lamp light-transmissive ceramic enclosure
101
looses a hermeticity. However, such a problem could be solved in easy according to the present invention.
SUMMARY OF THE INVENTION
The present invention has an object to provide an enhanced high-intensity discharge lamp, an enhanced high-intensity discharge lamp device, an enhanced high-intensity discharge lamp lighting circuit, and an enhanced lighting device using the lamp, in which feed-conductors fail to be off-centered from the refractory portions, and/or that they present high-reliability of sealing between the discharge lamp light-transmissive ceramic enclosure and the feed-conductor
Further, the present invention has another object to provide a high-intensity discharge lamp device in which the high-intensity discharge lamp would not be reduced its life-expectancy even if a shallow reflector is utilized.
Furthermore, the present invention has still another object to provide a compact high-intensity discharge lamp lighting circuit and a lighting system using the discharge lamp lighting circuit which is able to be miniaturized by using the stabilizer capable of starting the lighting operation by its load characteristics similar to that of a fluorescent lamp stabilizer, and which presents a relatively low blackening level, i.e., blackening due to an evaporation of an electrode material at a glow-arc transition.
A high-intensity discharge lamp accord
Toshiba Lighting & Technology Corporation
Vu David
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