JPH0982285A - High-pressure electric discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-pressure electric discharge lamp having the capability of properly and permanently stopping the generation of pulse voltage, when a light emitting tube falls in such a state as unable to start for any reason. SOLUTION: An outer tube 6 is internally provided with a light emitting tube 1 having a pair of electrodes at both ends thereof and containing starting rare gas sealed inside, and a starter 2 to apply pulse voltage across the electrodes of the light emitting tube 1. The starter 2 is formed out of a glow starter 2a and a heat generating resistance body 2b, and a serial circuit formed out of the starter 2, a normally close first thermally-actuated switch 3 and an electric current fuse element 4 is connected in parallel to the light emitting tube 1. In addition, a normally open second thermally-actuated switch 5 is connected in parallel to the starter 2. The second thermally-actuated switch 5 closes a circuit, due to heat generated with the heat generating resistance body 2b of the starter 2, thereby blowing the electric current fuse element 4.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to high pressure discharge lamps.

[0002]

2. Description of the Related Art Conventionally, as a high-pressure discharge lamp such as a high-pressure sodium lamp, as shown in FIG. 5, a starter 16 composed of a series body of a normally-closed thermal response switch 16a and a heating resistor 16b, and a normally-closed body. The parallel body of the heat-responsive switch 17 and the arc tube 1 is connected in parallel to form a parallel body, and the parallel body of the heating resistor 18 and the heat-responsive switch 19 is connected in parallel with the parallel body. It is known that the heating resistor 18 is arranged close to the normally closed thermal response switch 17 (JP-A-7-105913).

[0003]

With such a structure, when the arc tube 1 does not start for some reason, current continues to flow in the series body of the heating resistor 18 and the thermal response switch 19, and the heating resistor is generated. The body 18 generates heat, and the heat-responsive switch 17 arranged near the heat generating resistor 18 is opened by the heat of the heat generating resistor 18 to stop the generation of the pulse voltage.

However, since the high-pressure discharge lamp does not permanently disable the starter 16 itself, when the application of the power supply voltage to the high-pressure discharge lamp is stopped, the initial state is restored and Since the generation of the pulse voltage is repeated for a certain period each time the power is turned on, it was not possible to permanently stop the generation of the pulse voltage.

The present invention provides a high pressure discharge lamp capable of reliably and permanently stopping the generation of pulse voltage when the arc tube cannot be started for some reason.

[0006]

The high-pressure discharge lamp of the present invention has a pair of electrodes at both ends, and a pulse voltage is applied between the arc tube in which a rare gas for starting is sealed and the electrodes of the arc tube. A high pressure discharge lamp having a starter for applying in an outer tube, wherein the starter comprises a glow starter and a heating resistor, and the first starter and the normally closed first parallel to the arc tube. Connecting a series body of the heat-actuated switch and the current fuse element, a second heat-actuated switch that is normally open is connected in parallel with the starter, and the second heat-actuated switch is the starter. The heating fuse of the container is closed by the heat of the heating resistor to blow the current fuse element.

In the above structure, it is preferable that the heat generating resistor of the starter has a flat plate shape. In the above configuration,
It is preferable that the heating resistor of the starter is a ceramic-coated heater.

In the above structure, the heating resistor of the starter is made of a ceramic-coated heater, and the ceramic-coated heater, the second thermal responsive switch, and the current fuse element are integrally provided. preferable.

In the above structure, it is preferable that the second thermoresponsive switch is arranged on the side opposite to the arc tube with respect to the heating resistor.

[0010]

In the high-pressure discharge lamp of the present invention, when the arc tube does not start for some reason even when the power supply voltage is applied to the high-pressure discharge lamp, the heat of the heat-generating resistor causes the second heat-actuated switch to be closed, and By melting the fuse element, the high-pressure discharge lamp is permanently disabled. That is, if the arc tube does not start for some reason even when the power supply voltage is applied to the high-pressure discharge lamp, the first thermoresponsive switch that opens due to the heat of the arc tube during lighting remains in the closed state because the arc tube does not light. Therefore, the contact of the glow starter repeats opening and closing, and the pulse voltage continues to be generated from the ballast, so the current limited by the heating resistor continues to flow intermittently in the starter, and the heating resistor causes the heating resistor to Heat is generated and the temperature rises. When the normally open second thermo-responsive switch, which is arranged close to the heating resistor, is heated by the heating resistor to reach the closed circuit temperature and the contact point is closed, the short-circuit current of the ballast is closed. The current fuse element flows through the second heat-responsive switch, and the current fuse element is blown.

When the current fuse element is blown in this way, no current can flow through the starter, so the starter is permanently inoperable, and thereafter, a pulse voltage is generated even when the power is turned on again. There is no such thing.

Further, since the heating resistor of the starter has a flat plate shape, the heat generating switch has a large heat generating area, so that heat can be reliably transmitted to the heat responsive switch.

Further, since the heating resistor of the starter is made of a ceramic-coated heater, the heating resistor can be downsized and light emission when the lamp is turned on can be prevented.

Further, since the heating resistor of the starter is made of a ceramic-coated heater, and the ceramic-coated heater, the second thermoresponsive switch, and the current fuse element are integrally provided, the parts are put together. It can be made compact, and when it is used, it does not interfere with the light emission when the lamp is on.

Further, since the second heat-responsive switch is arranged on the side opposite to the light emitting tube with respect to the heating resistor, it becomes difficult to receive heat radiation from the light emitting tube during stable lighting of the high pressure discharge lamp. It is possible to design with a margin against the phenomenon that the second thermo-responsive switch opens before the first thermo-responsive switch opens.

[0016]

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

The high pressure sodium lamp with a built-in starter according to the first embodiment of the present invention shown in FIG. 1 has a pair of electrodes at both ends, and sodium and mercury, as well as a rare gas for starting xenon and the like are contained therein. It has an arc tube 1 made of a translucent alumina ceramic filled with gas. The arc tube 1 is connected in parallel with a series body of a starter 2, a normally closed first thermoresponsive switch 3 and a current fuse element 4. The starter 2 is composed of a glow starter 2a and a heating resistor 2b for limiting a current flowing through the glow starter 2a, which are connected in series. The first heat-responsive switch 3 is for opening the circuit by the radiant heat from the arc tube 1 to interrupt the current supply to the starter 2 during stable lighting of the high pressure discharge lamp. The current fuse element 4 is constructed so that it blows out instantly when a current significantly larger than the current value determined by the heating resistor 2b flows. The second thermoresponsive switch 5 is connected in parallel with the starter 2. One end of the second thermoresponsive switch 5 is a connection point between one electrode of the arc tube 1 and the starter 2, and the other end of the second thermoresponsive switch 5 is a connection between the starter 2 and the current fuse element 4. Connected to each point. The second heat-responsive switch 5 is arranged close to the heating resistor 2b, does not operate at the temperature inside the outer tube 6 during stable lighting of the high pressure discharge lamp, and is always in an open circuit state. When the body 2b is heated by self-heating and reaches a certain temperature higher than the temperature during stable lighting of the high pressure discharge lamp, the body 2b is closed.

The proximity conductor 7 is arranged in contact with the outer surface of the arc tube 1 and is connected to one electrode of the arc tube 1 via a third thermal response switch 8. The third heat-responsive switch 8 is for opening the circuit by the radiant heat from the arc tube 1 during stable lighting of the high-pressure discharge lamp so that no potential is applied to the adjacent conductor 7. 9 indicates a ballast, and 10 indicates an AC power source, respectively.

When a power supply voltage is applied to the high-pressure sodium lamp thus constructed through the ballast 9, the glow starter 2a of the starter 2 starts the opening / closing operation and a pulse voltage is generated between the terminals of the ballast 9. When the arc tube 1 starts to discharge due to this pulse voltage, the arc tube voltage drops, so that the glow starter 2a stops operating and the current flowing to the starter 2 also stops. When the arc tube 1 starts normally and shifts to stable lighting, the radiant heat of the arc tube 1 opens the first heat-responsive switch 3, so that the starter 2, the current fuse element 4, and the first heat-responsive switch 3 are connected. No current flows in the series body. The current flowing through the starter 2 when the power supply voltage is applied is determined by the impedance of the ballast 9 and the resistance value of the heating resistor 2b, and the fusing current of the current fuse element 4 is set sufficiently higher than that. Therefore, the current fuse element 4 is not blown by this current. Further, in a state where the arc tube 1 operates normally, the time from application of the power supply voltage to the start of discharge of the arc tube 1 is several seconds at the longest, and therefore, the heating resistor 2b during this period. The second heat-responsive switch 5 does not reach the closed circuit temperature even if it is heated by.

By any chance, at the end of the life of the high pressure discharge lamp, the starting voltage of the arc tube 1 rises remarkably, or a part of the current supply line to the arc tube 1 is cut off by a mechanical shock from the outside. Then, when the arc tube 1 is in a non-startable state, naturally, the arc tube 1 does not start discharging even if the power supply voltage is applied. In this case, by continuing to apply the power supply voltage, the glow starter 2a continues to open and close, and the current continues to flow intermittently in the starter 2.
b will generate heat excessively. When the second heat-responsive switch 5 reaches the closed circuit temperature due to the heating by the heating resistor 2b, the contact closes and a large current determined only by the impedance of the ballast 9 causes a current fuse element through the second heat-responsive switch 5. 4, the current fuse element 4 is melted and the starter 2 is permanently cut off. Therefore, thereafter, even if the high-voltage discharge lamp is left with the power supply voltage applied, or even if the power supply voltage is repeatedly turned on, no pulse voltage is generated and the state is extremely safe.

As the heating resistor 2b in the above embodiment, a normal carbon film resistor may be used. Further, as the heating resistor 2b, as shown in FIG. 2, a flat ceramic-coated heater may be used. Further, the second heat responsive switch 5 and the current fuse element 4 may be provided on the surface of the ceramic coated heater to be integrated (unitized). The ceramic coated heater shown in FIG. 2 has terminals 11, 12 of the second thermal response switch 5, the current fuse element 4 and the heating resistor 2b, one terminal 13 of the second thermal response switch 5, the current fuse element 4 and the like. Is provided with a terminal 14 for connecting one end thereof to the first heat-responsive switch 3 and a mounting terminal 15 for holding the entire unit at an appropriate position in the outer tube 6 of the high pressure discharge lamp. .

Next, 220 having the circuit configuration shown in FIG.
The high-pressure sodium lamp with a built-in starter of W will be described.

In FIG. 1, the second heat-responsive switch 5 has a bending constant of 10.9 × 10 ^-6 / ° C. and a thickness, width and length of 0.2 mm, 5 mm and 18 m, respectively.
A switch having a measured closed circuit temperature of about 350 ° C. was constructed by using a bimetal piece of m, the contact spacing of 5 mm. As shown in FIG. 3, the second thermal switch 5 is a heating resistor 2
b, that is, at a position 3 mm away from the surface of the ceramic-coated heater, the surface of the bimetal piece of the second thermoresponsive switch 5 and the surface of the ceramic-coated heater are mounted so as to be substantially opposed to each other. In addition, the unit shown in FIG.
The second heat-responsive switch 5 is mounted inside the outer tube 6 in a direction in which it is shielded from the arc tube 1 by a flat-plate ceramic-coated heater. As a result, it becomes difficult to receive heat radiation from the arc tube during stable lighting of the high-pressure discharge lamp, and there is a margin for the phenomenon that the second thermal response switch opens before the first thermal response switch opens. Design becomes possible.

The first thermoresponsive switch 3 and the third thermoresponsive switch 8 each have an open circuit temperature of about 150 ° C.,
Both of them were attached to the outer tube 6 as close as possible to the arc tube 1 and away from the starter 2.

This high pressure sodium lamp is
When it was connected to a 200 V AC power source through the ballast for the W high-pressure mercury lamp, the arc tube 1 started normally and transitioned to a stable lighting state through the process described above. After confirming that the arc tube started normally, in order to test the operation of the high pressure discharge lamp in the state where the arc tube could not be started, turn off the high pressure discharge lamp and use the laser beam to cool the outer tube. The current supply line to the arc tube 1 was cut inside the outer tube 6 so as not to destroy the arc tube 6, and the arc tube 1 was put into a state where it could not be started. When the power supply voltage is applied to the high-pressure discharge lamp in this state, the current continues to flow to the starter 2 and the temperature of the ceramic coating heater 2b as the heating resistor 2b rises rapidly, and after a few tens of seconds, the second thermal response switch is activated. It was confirmed that the current fuse element 4 was melted by closing 5 and the starter 2 was cut off by this melting, and the generation of the pulse voltage from the ballast was permanently stopped.

Incidentally, FIG. 4 shows a circuit configuration when an arc tube having an auxiliary electrode is used. The current limiting resistance 20 in FIG. 4 is for suppressing the current to the auxiliary electrode, and the same effect as that of the above-described embodiment can be obtained. Although the high-pressure sodium lamp has been described in the above embodiment, the same effect can be obtained also in a metal halide lamp in which a rare gas such as argon is enclosed in an arc tube together with mercury and a metal halide.

[0027]

As described above, the present invention is
At the end of the life of the discharge lamp, the starting voltage of the arc tube remarkably rises or a part of the current supply line to the arc tube is cut by a mechanical shock from the outside. The starter operation is stopped quickly and surely,
It is possible to provide a high-pressure discharge lamp that can permanently stop the generation of a pulse voltage and can prevent a decrease in insulation of a starter or a lighting circuit wiring and an abnormal temperature rise of a ballast.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a high pressure discharge lamp which is a first embodiment of the present invention.

FIG. 2 is a diagram showing a unit of the same parts.

FIG. 3 is a diagram showing the position of the second thermal switch as well.

FIG. 4 is a circuit diagram when an arc tube having an auxiliary electrode is also used.

FIG. 5 is a circuit diagram of a conventional high pressure discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 luminous tube 2 starter 2a glow starter 2b heating resistor 3 first thermal response switch 4 current fuse element 5 second thermal response switch 6 outer tube

Continuation of the front page (72) Inventor Gion Hong 1-1, Saiwaicho, Takatsuki City, Osaka Prefecture Matsushita Electronics Industrial Co., Ltd.

Claims (5)

[Claims] 1. An outer tube is provided with an arc tube having a pair of electrodes at both ends and having a starting rare gas sealed therein, and a starter for applying a pulse voltage between the electrodes of the arc tube. A high-pressure discharge lamp in which the starter comprises a glow starter and a heating resistor, and the starter, a normally-closed first thermoresponsive switch, and a current fuse element are connected in series in parallel with the arc tube. And a normally open second thermo-responsive switch is connected in parallel with the starter, and the second thermo-responsive switch is closed by the heat of the heating resistor of the starter. A high pressure discharge lamp provided so as to blow the current fuse element. 2. The high pressure discharge lamp according to claim 1, wherein the heating resistor of the starter has a flat plate shape. 3. The high pressure discharge lamp according to claim 1, wherein the heating resistor of the starter comprises a ceramic coated heater. 4. The heating resistor of the starter comprises a ceramic-coated heater, and the ceramic-coated heater, the second thermal response switch, and the current fuse element are integrally provided. The high pressure discharge lamp according to any one of claims 1 to 3. 5. The high-voltage discharge according to claim 1, wherein the second heat-responsive switch is arranged on the side of the heating resistor opposite to the arc tube. lamp.