Electric lamp and discharge devices – With luminescent solid or liquid material – With gaseous discharge medium
Reexamination Certificate
2000-10-24
2003-02-04
Kim, Robert H. (Department: 2882)
Electric lamp and discharge devices
With luminescent solid or liquid material
With gaseous discharge medium
C313S318050, C313S318060, C313S318010
Reexamination Certificate
active
06515412
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fluorescent lamp.
2. Description of the Related Art
Conventionally, during the last period of the life of a fluorescent lamp, when all electron emitting substances filled into an electrode filament coil dissipate, a cathode drop voltage rises and power consumption in an electrode increases. Thus, the temperature in the vicinity of an electrode sealing portion on the end of a light-emitting tube is excessively increased, and heat generation may occur. As a method for preventing such a rise in temperature or excessive heat generation from occurring, the following has been known: A thermal fuse or the like is provided in the vicinity of the end of the light-emitting tube. The excessive heat generated in the end of the light-emitting tube melts and cuts off this thermal fuse, so that a lighting circuit is interrupted (see JP 2-192650A and JP 4-61740A).
In recent years, a compact one-base-type fluorescent lamp with a small tube diameter has been developed and commercially expanded as an energy-saving light source to be substituted for light bulbs or the like. When such a fluorescent lamp is lit by a high-frequency electronic circuit, a preheating current may continue to flow through the electrode filament coil depending on the electronic circuit system, even if the lamp cannot light up because of the dissipation of all the electron emitting substances in the last period of lamp life.
In this case, the glass temperature of the electrode sealing portion rises excessively because an arc discharge or the like is generated between the electrode lead wires holding the electrode filament coil, thereby causing a breakdown. Thus, the preheating current flows in the glass between the electrode lead wires to increase the temperature of the electrode sealing portion excessively.
For one-base-type fluorescent lamps, a rise in temperature of the electrode sealing portion is especially remarkable, and thus a base made of a resin material may be deformed by heat. In order to prevent such a rise in temperature, the high-frequency electronic circuit is generally provided with a so-called protection circuit for detecting the dissipation of all the electron emitting substances in the electrode and stopping the electronic circuit operation. However, even if such a protection circuit is provided, the failure of the protection circuit, though it rarely occurs, may cause the above-mentioned base deformation or the like. As a method for preventing such a rise in temperature of the electrode sealing portion that leads to the base deformation or the like, the following has been known: A thermal protection element, such as a thermal fuse or the like is provided in the base so as to be connected in series with an outer electrode lead wire (see JP 10-188906A and JP 11-111231A).
FIG. 33
shows an example of a configuration of a one-base-type fluorescent lamp according to the conventional techniques. In a light-emitting tube
137
(with an outer diameter of about 17 mm) having a pair of electrodes therein, four straight glass tubes
138
,
139
,
140
, and
141
are joined to form a discharge path therein. A base
142
is provided on the end of the tube of the light-emitting tube
137
. Base contact pin terminals
145
,
151
,
152
, and
153
are provided on the base
142
and connected to electrode lead wires
144
,
148
,
149
, and
150
drawn from the light-emitting tube
137
, respectively. In the base
142
, a thermal protection element
143
that acts as a thermal fuse is connected to the electrode lead wire
144
drawn from the light-emitting tube
137
and the base contact pin terminal
145
by caulking.
In addition to the four straight tubes type described above, two, six, and eight straight tubes types conventionally have been known as the one-base-type fluorescent lamps. Among these types, e.g., in the one-base-type fluorescent lamp of four straight tubes type provided with the thermal protection element (hereinafter referred to as a thermal fuse)
143
, as shown in
FIG. 33
, the base
142
generally includes a light-emitting tube holding member
146
and a base body
147
that mainly are made of a resin material, as shown in FIG.
34
.
In the manufacturing processes for this type of fluorescent lamp, first, the ends of the four tubes of the light-emitting tube
137
are inserted into circular holes of the light-emitting tube holding member
146
, and then fixed with an adhesive of a silicone resin or the like. Then, one end of the thermal fuse
143
and one end of the electrode lead wire
144
are connected. Then, the light-emitting tube holding member
146
and the base body
147
are fixed. Finally, the remaining three electrode lead wires
148
,
149
, and
150
and the other end of the thermal fuse
143
are connected to the base contact pin terminals
151
,
152
,
153
, and
145
attached to the base body
147
by soldering or caulking. Also, in the two, six, and eight straight tubes types (with an outer diameter of the light-emitting tube of about 12 mm or about 17 mm), the base includes two parts that are basically the same as in the above four straight tubes type. In addition, the base assembly process is basically the same.
On the other hand, as an example of the kind of high wattage lamp of the two straight tubes type (with an outer diameter of the light-emitting tube of about 20 mm, and the electric power of 28 W. 36 W. 55 W, or 96 W), a lamp with the structure shown in
FIGS. 35
,
36
, and
37
is provided.
FIG. 35
is a sectional front view of a base portion, and
FIGS. 36 and 37
are plan views thereof. In this lamp, a base
154
is provided with a base body
155
, two covers
156
,
157
shown in
FIG. 37
, and two thermal fuses
158
,
159
shown in FIG.
36
.
FIG. 36
is a plan view of a base not including the covers
156
,
157
.
In the manufacturing processes for this type of fluorescent lamp, the thermal fuses
158
,
159
are accommodated in the predetermined positions in the base body
155
. Then, one side lead wire of each of the thermal fuses
158
,
159
is inserted into respective base contact pin terminals
160
,
161
. At the same time, electrode lead wires
166
,
167
drawn from a light-emitting tube
164
are inserted into base contact pin terminals
163
,
162
, respectively. Then, the light-emitting tube
164
is fixed in the base body
155
with a silicon adhesive or the like. The electrode lead wires
166
,
167
, and the one side lead wire of each of the thermal fuses
158
,
159
that have been inserted into the base contact pin terminals
160
,
161
,
162
, and
163
, then are connected to the base contact pin terminals
160
,
161
,
162
, and
163
, respectively, by caulking. Furthermore, electrode lead wires
165
,
168
and the other side lead wire of each of the thermal fuses
158
,
159
are connected by caulking terminals
169
made of metal, and then the connected portions are inserted into the base body
155
to which the two covers
156
,
157
are attached.
In a conventional fluorescent lamp without the thermal fuse, e.g., when a base is attached, electrode lead wires are arranged straight so as to be led to base contact pin terminals. Thus, when the end of a light-emitting tube is inserted into the base, the electrode lead wires spontaneously are led to and inserted into the corresponding base contact pin terminals, respectively. Therefore, for the conventional fluorescent lamp without the thermal fuse, the processes from the manufacture of a fluorescent lamp to base assembly generally are performed by a series of automatic manufacturing equipment or the like, so that mass production easily is achieved, and thus the manufacturing cost of lamps can be lowered.
However, for a conventional fluorescent lamp with the thermal fuse described above, in its manufacturing processes, it is difficult to connect the lead wires of the thermal fuse to an electrode lead wire of the light-emitting tube and a base contact pin terminal by automation, and thus these connectio
Higashino Hiroaki
Hirai Kenji
Ishitsuka Shinichiro
Kuboki Yasuo
Tani Seido
Barber Therese
Kim Robert H.
Matsushita Electric - Industrial Co., Ltd.
Merchant & Gould P.C.
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