JP3076711B2 - High pressure sodium lamp with built-in starter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high pressure sodium lamp with a built-in starter.

[0002]

2. Description of the Related Art High-pressure sodium lamps are used in a wide range of fields such as factory lighting, road lighting, and tunnel lighting because of their high efficiency.

[0003] Since it is difficult to start a high-pressure sodium lamp with a commercial power supply voltage, a high-pressure pulse is required to start the lamp. Conventionally, a ballast with a built-in pulse generator is used. . However, in recent years, a high-pressure sodium lamp with a built-in starter having a built-in device for generating a pulse voltage in an outer tube has become mainstream so that it can be operated in combination with a ballast for a high-pressure mercury lamp. FIG. 7 is a circuit diagram of such a lamp. In this lamp, a starter 9 composed of a series body of a filament 2 and a normally-closed bimetal switch 3 is connected in parallel to an arc tube 1, and a proximity auxiliary conductor 7 is attached near the arc tube 1 as an auxiliary for starting. I have. Then, by applying a power supply voltage to this circuit via a ballast, a current flows through the starter 9 and the bimetal switch 3 is heated by the heat generated by the filament 2. After a certain period of time, the bimetal switch 3 is opened. At this time, a sudden change in current generates a high-voltage pulse from the choke coil of the ballast, and this pulse is applied to the arc tube 1 and the proximity auxiliary conductor 7 together with the power supply voltage. And the lamp starts.

[0004]

Although such a high pressure sodium lamp with a built-in starter can use an inexpensive ballast for a high pressure mercury lamp, it is necessary to consider a phenomenon that occurs at the end of life. That is, in general, a high-pressure sodium lamp leaks at the end of its life, for example, at the electrode sealing portion of the arc tube 1, and the starting rare gas, metal for buffer gas, and sodium sealed in the arc tube 1 from this leak point. Leakage may occur in the outer tube 8. Normally, when such a leak phenomenon occurs, once the lamp is turned off and then turned on again, discharge occurs between the filaments of the starter in the outer tube, which may cause the filament to be broken and cannot be started. In most cases, the filament of the starter may light up without breaking.

In such a case, the lamp voltage gradually decreases, and the lamp current increases accordingly. And if such a state continues, a ballast will burn out.
In the case of a ballast having a built-in temperature fuse or current fuse, the fuse may be blown and may not be able to function as a ballast.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points. In order to solve the problem of destruction of the function of a ballast such as burnout of a ballast at the end of lamp life, safety measures such as ballast protection are required. A high pressure discharge lamp having a function is provided.

[0007]

A high pressure sodium lamp with a built-in starter according to the present invention is provided with an arc tube in which a rare gas for starting, a metal for buffer gas and sodium are sealed, and which is provided in an outer tube. And a starter consisting of a series body of a filament, a bimetal switch and a current fuse are connected in parallel, and discharge occurs when a light emitting tube leaks between the current fuse and the filament or between the bimetal switch and the current fuse. One end of the discharge electrode at the time of leakage is connected, and the other end of the electrode for discharge at the time of leakage is provided close to the filament. Further, in the starter-incorporated high-pressure sodium lamp of the present invention, an arc tube in which a starting rare gas, a buffer gas metal and sodium are sealed is provided in an outer tube,
A starter consisting of a series body of a filament, a bimetal switch and a current fuse is connected in parallel to the arc tube, and an arc tube leak is caused between the bimetal switch and the filament or between the bimetal switch and the current fuse. One end of a discharge electrode at the time of leakage that is discharged at the time is connected, and the other end of the electrode for discharge at the time of lead is provided close to the filament, and between the bimetal switch and the filament, or the bimetal switch. A getter is connected between the current fuse and the current fuse.

[0008]

According to this structure, starting rare gas, metal for buffer gas, and sodium, which are sealed in the arc tube, leak into the outer tube due to, for example, leakage of the electrode sealing portion of the arc tube at the end of lamp life. In this case, once the lamp is turned off and then turned on again, a discharge is reliably generated between the filament of the starter in the outer tube and the discharge electrode at the time of leakage provided close to the filament, or Discharge is reliably generated between the filament and the getter, and the current fuse is blown by this discharge current to stop the generation of the high-voltage pulse voltage.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 2 and 3, the 220 W starter built-in high-pressure sodium lamp according to one embodiment of the present invention comprises a translucent alumina tube having an internal volume of 2.7 cc and a length of 81 mm. 32 mg of sodium / mercury amalgam with a sodium ratio of 13% and xenon gas 2 as a starting rare gas
The arc tube 1 filled with 50 Torr has an inner volume of 750 cc.
Is provided in the outer tube 8. And in the arc tube 1,
A filament 2 having a total length of 220 mm and a power consumption of 150 W;
Bimetal switch 3, wire diameter 0.26mm, length 10mm
A starter 6 composed of a series body of a current fuse 4 composed of a Monel wire is connected in parallel, and one end of a discharge electrode 5 for leakage that is discharged between the bimetal switch 3 and the current fuse 4 at the time of arc tube leakage is formed. The other end of the discharge electrode 5 at the time of leakage is provided near the filament 2.

FIG. 1 shows a circuit diagram of a starter 6. A series body composed of a filament 2, a bimetal switch 3, and a current fuse 4 is connected in parallel to the arc tube 1, and the bimetal switch 3 and the current One end of the discharge electrode for leakage 5 is connected to the fuse 4 and the other end of the discharge electrode 5 for leakage is provided near the filament.

The electrode 5 for discharging at the time of leakage has a wire diameter of 1.2 mm.
A tungsten wire with a wire diameter of 0.6 mm on
A 400 W mercury lamp electrode wound around a layer and coated and baked with a Ba-Ca-ThO ₂ -based electron-emitting substance is used. The proximity conductor 7 is attached near the arc tube 1 as a starting aid.

The inside of the outer tube 8 is normally kept in a vacuum, but when the xenon gas sealed in the arc tube 1 completely leaks into the outer tube 8, the inner volume of the outer tube 8 is 750 cc. The gas pressure in the outer tube 8 becomes 0.9 Torr.

The present invention, in the initial stage of this leak,
Discharge is reliably generated between the filament 2 of the starter 6 and the discharge electrode 5 at the time of leakage provided in the vicinity of the filament 2, and the current fuse 4 is blown by the discharge current to generate a high-voltage pulse voltage. Since the purpose is to stop the operation, 0.9 Torr of xenon gas is sealed in the outer tube 8 in advance, assuming leakage of the arc tube 1.

When this lamp was manufactured and connected to a 250 W mercury lamp ballast and power was applied, the filament 2 glowed red, and at the same time, a discharge was generated between the filament 2 and the discharge electrode 5 at the time of leakage. Thereafter, a discharge current of about 4 A flowed through the current fuse 4, the current fuse 4 glowed and melted, and the lamp did not light. Further, once the power was turned off and the lamp was left for a long time, the power was applied again, but the lamp did not light again.

Further, in this embodiment, a series body in which the filament 2, the bimetal switch 3, and the current fuse 4 are sequentially connected is used, and one end of the discharge electrode 5 for leakage is connected between the bimetal switch 3 and the current fuse 4. An experiment was performed using a starter 6 provided with the other end of the discharge electrode 5 at the time of leakage close to the filament 2.
One end of the discharge electrode 5 at the time of leakage is connected between the current fuse 4 and the filament 2 using a series body sequentially connected to the filament 2 and the bimetal switch 3, and the other end of the discharge electrode 5 at the time of leakage is connected. Similar results were obtained using starter 6 connected to filament 2. A similar experiment was repeated for each of the ten lamps, with similar results.

Next, another embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 5 and 6, a 220 W starter built-in high-pressure sodium lamp according to another embodiment of the present invention has the same structure as that of the above-described embodiment of the present invention. 220mm power consumption 150
A starter 6 composed of a series body of a W filament 2, a bimetal switch 3, and a current fuse 4 composed of a Monel wire having a wire diameter of 0.26 mm and a length of 10 mm is connected in parallel,
One end of a discharge electrode at the time of leakage 5 that discharges when an arc tube leaks is connected between the bimetal switch 3 and the current fuse 4, and the other end of the discharge electrode 5 at the time of leakage is provided near the filament 2. Have been. Further, a ring getter 9 made of barium is connected between the Bimel switch 3 and the current fuse 4.

FIG. 4 is a circuit diagram of the starter 6.
The arc tube 1 has a filament 2 and a bimetal switch 3
And a series body of current fuses 4 are connected in parallel, and one end of a discharge electrode 5 for leakage that discharges when the arc tube leaks is connected between the bimetal switch 3 and the current fuse 4. The other end of the electrode 5 is provided close to the filament 2. Further, a ring getter 9 made of barium is connected and provided between the Bimel switch 3 and the current fuse 4.

When this lamp was prototyped and connected to a 250 W mercury lamp ballast and power was applied, simultaneously with the red heat of the filament 2, between the filament 2 and the discharge electrode 5 at the time of leakage, and between the filament 2 and the getter 9. And a half-wave discharge occurs between them, and a few seconds later, a discharge current of about 4 A flows through the current fuse 4, and the current fuse 4 glows red and melts,
The lamp did not light. The power was turned off, the lamp was left for a long time, and then the power was applied again, but the lamp did not light.

Further, in another embodiment of the present invention, one end of a discharge electrode 5 for leakage is provided between the bimetal switch 3 and the current fuse 4 by using a series body in which the filament 2, the bimetal switch 3 and the current fuse 4 are sequentially connected. Connect the parts
In addition, the experiment was performed using a starter 6 provided with the other end of the discharge electrode at the time of leakage in the vicinity of the filament 2 and further connected with a barium ring getter 9 between the bimetal switch 3 and the current fuse 4. A series connection of a current fuse 4, a filament 2 and a bimetal switch 3 is used to connect one end of a leakage discharge electrode 5 between the current fuse 4 and the filament 2; 5 is provided near the filament 2,
Similar results were obtained when a barium ring getter 9 was provided between the current fuse 4 and the filament 2. The same experiment was repeated ten times for each lamp, and similar results were obtained.

Further, in this embodiment, when the current fuse used is red-heated by the current flowing through the filament of the starter at the time of starting the lamp, the fuse material evaporates and the fusing characteristics are liable to change. There is.
In addition, there is a step of causing an overcurrent of less than 2 A to manufacture the lamp to prevent the filament from being deformed during its life and causing the filament to recrystallize. In view of such a point, the fusing current of the current fuse needs to be set to 2A or more.

In this embodiment, the 220 W high pressure sodium lamp with a built-in starter has been described. However, it was recognized that the same result was obtained regardless of the lamp wattage.

The discharge electrode 5 at the time of leakage is made of Ba-C
a-ThO ₄ type electron-emitting material was coated and baked 40
Although an electrode for a 0 W mercury lamp was used, the same applies to an electrode obtained by applying and baking a substance mainly composed of an alkaline earth metal having a low work function such as Ba or Ca, or a metal containing an electron-emitting substance such as thoriated tungsten. Was obtained.

[0024]

As described above, the high-pressure sodium lamp with a built-in starter according to the present invention is capable of reducing the occurrence of a rare gas for start-up sealed in an issuance tube due to, for example, a leak at the electrode sealing portion of the arc tube occurring at the end of life. If the buffer gas metal or sodium leaks into the outer tube, once this lamp is turned off and turned on again, between the filament of the starter in the outer tube and the leakage discharge electrode provided in the vicinity of the filament, Alternatively, it is possible to more reliably generate a discharge between the filament of the starter and the getter, blow the current fuse by this discharge current, and stop the generation of the high-voltage pulse voltage. As a result, the starter that generates the high-voltage pulse can have a self-destructive function, and can have a safety function to protect the ballast.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a high-pressure sodium lamp with a built-in starter according to an embodiment of the present invention.

FIG. 2 is also a front view

FIG. 3 is a front view of the same starter.

FIG. 4 is a circuit diagram of a high-pressure sodium lamp with a built-in starter according to another embodiment of the present invention.

FIG. 5 is a front view of the same.

FIG. 6 is a front view of the starter.

FIG. 7 is a circuit diagram of a conventional high pressure sodium lamp with a built-in starter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 2 Filament 3 Bimetal switch 4 Current fuse 5 Discharge electrode at the time of leak 6 Starter 8 Outer tube 9 Getter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-86152 (JP, A) JP-A-61-128444 (JP, A) JP-A-61-173438 (JP, A) JP-A 64-64 31345 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 61/56

Claims (4)

(57) [Claims] An arc tube in which a starting rare gas, a buffer gas metal and sodium are sealed is provided in an outer tube, and the arc tube has a starter composed of a series body of a filament, a bimetal switch, and a current fuse. One end of a discharge electrode at the time of leakage that discharges at the time of arc tube leakage is connected between the current fuse and the filament, or between the bimetal switch and the current fuse, and connected in parallel. A high pressure sodium lamp with a built-in starter, wherein the other end of the time discharge electrode is provided close to the filament. 2. An arc tube in which a starting rare gas, a buffer gas metal and sodium are sealed is provided in an outer tube, and the arc tube has a starter comprising a series body of a filament, a bimetal switch, and a current fuse. While being connected in parallel, one end of a discharge electrode at the time of leakage that discharges at the time of arc tube leakage is connected between the bimetal switch and the filament, or between the bimetal switch and the current fuse, and is connected to the lead during the lead. A starter wherein the other end of the discharge electrode is provided close to the filament, and a getter is connected between the bimetal switch and the filament or between the bimetal switch and the current fuse. Built-in high-pressure sodium lamp. 3. The high-pressure sodium lamp with a built-in starter according to claim 1, wherein a current fuse that blows with a sine wave current of at least 2 A in a vacuum is selected and used. 4. An electrode for discharging at the time of leakage, wherein an electron-emitting substance or a substance mainly composed of an alkaline earth metal is applied and baked, or a metal containing an electron-emitting substance is used. The high pressure sodium lamp according to claim 1 or 2, wherein the high pressure sodium lamp has a built-in starter.