JPH05325904A - High pressure electric discharge lamp - Google Patents

Abstract

PURPOSE:To prevent a heat damage to a stabilizer due to leakage of a high pressure sodium (Na) lamp light emitting tube so as to enhance safety by extinguishing the lamp light emitting tube to cut off a starter in the case where the light emitting tube leaks during operation of a lamp. CONSTITUTION:When a high pressure Na lamp light emitting tube 1 leaks so that noble gas sealed therein leaks into an outer tube 8, the noble gas is ionized in an electric field of a high electric discharge gap, thus starting glow discharge. The glow discharge is transferred to arc discharge, and accordingly, a first conductor 2 and a second conductor 3 are short-circuited for a short period. The light emitting tube 1 stops electric discharge because a voltage applied to both electrodes is abruptly decreased. A filament 6 is incandescently fused due to a short-circuiting current flowing in an electric discharge gap 10 and the filament 6. Since a starter 7 cannot be operated owing to the fusing, the light emitting tube 1 cannot be discharged electrically. Consequently, it is possible to prevent an overcurrent from flowing in a stabilizer 9 for a long period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure discharge lamp having a starter built-in, which has a starter connected in parallel with an arc tube and disposed inside a vacuum outer tube.

[0002]

2. Description of the Related Art Conventional high-pressure sodium lamps and metal halide lamps are lit by a single choke type ballast at a commercial power source of 200 V, and therefore a starting device is connected in parallel with the arc tube. The starter is usually a thermo-responsive switch such as a bimetal switch, a fixed resistor for limiting current, and a filament for heating the thermo-responsive switch connected in series. In some cases, a large filament having a function of limiting the current and a function of heating the heat-responsive switch is used. When the thermal switch is opened, a high-voltage pulse is generated and superposed on the power supply voltage and applied to the arc tube, so that the arc tube starts discharging. A high-pressure discharge lamp of this type is disclosed in, for example, JP-A-53-16475.

[0003]

In such a high-pressure discharge lamp, cracks are generated in the arc tube during the operation of the lamp or the airtightness of the sealed portion is lowered, so that the rare gas and the luminescent metal inside are prevented. A phenomenon called so-called leak that leaks into the vacuum outer tube may occur. In such a case, the pressure inside the arc tube decreases and the discharge current increases. If the lamp is turned off within a relatively short time and the power switch is turned on next time, arc discharge will occur between the filament and the conductor of another potential at the time of pulse generation, and the filament will melt down, so the arc tube Since it is not possible to start the discharge, the overcurrent does not flow for a long time. However, if the lamp is turned on for a long time without being turned off,
Since a large current continues to flow in the ballast, the thermal fuse provided in the ballast for overheat protection is blown. This also damages the ballast and renders it useless.

The life of the ballast is usually several times longer than that of the lamp. However, the leakage of the arc tube causes the life of the lamp to increase with the life of the lamp, resulting in a large economical loss. To solve this problem, the measures that have been proposed so far are to turn off the lamp that has leaked and the discharge current becomes large by turning off the power switch. Was to turn off. That is, the configuration is such that it does not function unless the lamp is turned off once.

An object of the present invention is to provide a leak if the arc tube leaks.
An object of the present invention is to provide a highly safe high-pressure discharge lamp having a function of turning off the lamp without turning off the power switch so that the lamp cannot be started again.

[0006]

[Means for Solving the Problems] (1) 2
An arc tube having a light emitting metal and a rare gas enclosed therein, first and second conductors respectively connected to the electrodes and at least a filament for applying a voltage to the arc tube. In a high pressure discharge lamp in which a starting device connected in parallel with the arc tube is arranged in an outer tube whose inside is evacuated, the outer tube further has a discharge gap therein, and the discharge gap is A high-pressure discharge lamp, one end of which is connected to the filament and the other end of which is connected to a conductor different from the conductor to which the filament is connected. (2) Two electrodes are provided, and a luminescent metal is provided inside. An arc tube filled with a rare gas, having first and second conductors and at least filaments respectively connected to the electrodes for applying a voltage to the arc tube, and connected in parallel with the arc tube. In a high pressure discharge lamp in which a starting device is arranged in an outer tube whose inside is evacuated, the outer tube further has a discharge gap therein, and the discharge gap is provided when an arc discharge occurs between its electrodes. A high-pressure discharge lamp, characterized in that it is connected so as to melt at least a part of the filament, (3) above
Or the high-pressure discharge lamp according to 2, wherein the discharge gap has two electrodes holding an electron emitting material, (4) the high-pressure discharge lamp according to 3, The distance between the two electrodes is a value in the range of 1 to 20 mm. (5) In the high pressure discharge lamp according to any one of 1 to 4 above, the arc tube is , A high-pressure discharge lamp having a proximity conductor, (6)
The high-pressure discharge lamp according to any one of 1 to 5 above, wherein the starting device is a starting device in which the filament, a fixed resistor, and a thermoresponsive switch are connected in series. To be achieved.

[0007]

FIG. 1 shows an example of electrical connection of the high pressure discharge lamp of the present invention, and the operation of the present invention will be described with reference to this example. The electrodes at both ends of the high-pressure sodium lamp arc tube 1 are connected to the first conductor 2 and the second conductor 3, respectively. In parallel with the high-pressure sodium lamp arc tube 1, a starting device 7 including a fixed resistor 4, a bimetal switch 5 and a filament 6 is connected. One of the two terminals of the discharge gap 10 is connected to the conductor 2, and the other terminal is connected to one terminal of the filament 6. The other terminal of the filament is connected to the conductor 3. The bimetal switch 5 is open during normal lighting of the lamp. Also, the discharge gap 10
Does not discharge because it is placed in a vacuum.

Now, when the high pressure sodium lamp arc tube 1 leaks and the enclosed rare gas leaks into the outer tube 8,
The rare gas is ionized by an electric field with a high discharge gap to start glow discharge. Then, the arc discharge is started, and the first conductor 2 and the second conductor 3 are short-circuited for a short time. That is, the high-pressure sodium lamp arc tube 1 stops the discharge because the voltage applied between both electrodes thereof drops sharply. Then, the filament 6 is incandescently fused by the short-circuit current flowing through the discharge gap 10 and the filament 6. Since the starting device 7 does not operate due to the fusing of the filament 6, the high pressure sodium lamp arc tube 1 is not discharged. Therefore, it is possible to prevent the overcurrent from flowing to the ballast 9 for a long time.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high pressure discharge lamp according to an embodiment of the present invention will be described below with reference to FIG. Reference numeral 1 denotes a 360 W high-pressure sodium lamp arc tube in which electrodes are sealed at both ends of an alumina tube, and a metal such as metallic sodium or mercury and a rare gas are sealed inside. A first conductor 2 and a second conductor 3 are connected to both electrodes so that the electrodes at both ends have different potentials from each other. A starting device 7 is connected in parallel with the high pressure sodium lamp arc tube 1. Starter 7
Is a fixed resistor 4, bimetal switch 5, filament 6
Are connected in series. Fixed resistance 4 is about 300
The carbon film resistance is Ω, and the bimetal switch 5 is set to be closed at room temperature and to be opened when the temperature rises.
The filament 6 is a filament made of a fine metal wire such as tungsten. Reference numeral 10 is a discharge gap, in which two electrodes holding an electron emissive material such as barium oxide are provided.
It is fixed at intervals of mm. This interval is 1-2
It may be any desired value in the range of 0 mm. One of the two terminals of the discharge gap 10 is connected to the first conductor 2,
The other one terminal is connected to one terminal of the filament 6. The other terminal of the filament is connected to the second conductor 3.

Filament 6, bimetal switch 5,
The fixed resistor 4 is connected in series to form the starting device 7, one terminal of which is one terminal of the filament 6, and this terminal is connected to the second conductor 3. The other terminal of the starting device 7 is a terminal of the fixed resistor 4 and is connected to the first conductor 2. The fixed resistor 4 and the bimetal switch 5 may be arranged differently so that the other terminal of the starting device 7 is used as the terminal of the bimetal switch 5.

Further, in FIG. 1, the first conductor 2 and the second conductor 2
Even if the connection of the starting device 7 and the discharge gap 10 to the conductor 3 is reversed, the effect is the same. That is, even if one terminal of the filament 6 is connected to the first conductor 2 and the other terminal of the starting device 7 and one terminal of the discharge gap 10 are connected to the second conductor 3, the effect of the present invention does not change. ..

The high-pressure sodium lamp arc tube 1, the starting device 7, and the discharge gap 10 connected as described above are arranged in an outer tube 8 whose inside is evacuated, and connected to a 200 V power source through a choke type ballast 9. Light. The operation of the high-pressure sodium lamp will be described. When the high-pressure sodium lamp arc tube 1 is normal, the inside of the outer tube 8 is in a vacuum state, and therefore the discharge gap 10 does not discharge. That is, the power source 20
When 0V is applied, a current flows through the choke type ballast 9, fixed resistor 4, bimetal switch 5 and filament 6.
When the fixed resistance is 300Ω, a current of about 0.6A flows. The filament 6 glows red and heats the bimetal switch 5. This causes the bimetal plate to deform and the switch to open. At this time, the energy stored in the choke type ballast 9 generates a pulse voltage of 2 to 3 kV across the switch. At this time, this pulse voltage is also applied to the discharge gap 10, but no discharge occurs because the electrodes between the discharge gap 10 are in a vacuum. That is, this pulse voltage is applied between the electrodes of the high-pressure sodium lamp arc tube 1, and the discharge of the high-pressure sodium lamp arc tube 1 is started together with the action of the adjacent conductor 12 connected to the first conductor 2.

When the temperature of the high pressure sodium lamp arc tube 1 raises the temperature of the bimetal, the bimetal switch 11 opens. In this state, high pressure sodium lamp arc tube 1
When the rare gas therein leaks into the outer tube 8, the rare gas is ionized by the electric field between the electrodes of the discharge gap 10 to start glow discharge between the electrodes. Since the electron-emitting substance is held on both electrodes, it shifts to arc discharge and becomes short-circuited for several tens of milliseconds. At this time, the voltage applied to the high-pressure sodium lamp is close to zero, so the high-pressure sodium lamp arc tube 1 stops discharging. Then, the filament 6 is fused by an excessive current. An instantaneous pulse voltage is generated for melting, but since a rare gas exists in the outer tube 8, it is absorbed by the arc discharge generated at the filament melting point and is not applied to the arc tube. Therefore, the lamp will not light again.

As described above, the overcurrent prevention circuit in which the discharge gap 10 and the filament 6 which is a part of the starting device 7 are connected in series detects the leak of the high pressure sodium lamp arc tube 1 and stops the discharge. Then filament 6
The function of the starting device can be stopped by disconnecting.
That is, when the high-pressure sodium lamp arc tube 1 leaks, the high-pressure sodium lamp has a function of putting it in a no-load state, so that overcurrent does not flow or a pulse voltage is not applied to the ballast, and high-voltage discharge with high safety The lamp was obtained.

As a starting device, there is one in which a thermal switch and a filament for heating the switch are connected in series, and in this case, the resistance of the filament is large. When this starting device is used, one end of the discharge gap may be connected to the middle of the filament, and when arc discharge occurs in the discharge gap, a large current may flow and a part of the filament may be blown.

[0016]

According to the present invention, when the high-pressure sodium lamp arc tube leaks during the lamp operation, the high-pressure sodium lamp arc tube is turned off and the starting device is disconnected, so that the high-pressure sodium lamp arc tube is discharged again. There is nothing to do.
Therefore, it is possible to prevent the overcurrent from flowing for a long time and damaging the ballast.

[Brief description of drawings]

FIG. 1 is an electrical connection diagram of a high pressure discharge lamp of the present invention.

[Explanation of symbols]

 1 High-pressure sodium lamp arc tube 2 First conductor 3 Second conductor 4 Fixed resistance 5, 11 Bimetal switch 6 Filament 7 Starting device 8 Outer tube 9 Choke ballast 10 Discharge gap 12 Proximity conductor

Front page continuation (72) Inventor Kenji Miyata 888 Fujibashi, Ome city, Tokyo Metropolitan area Hirate factory Ome factory

Claims (6)

[Claims] 1. A light emitting tube comprising (1) two electrodes, wherein a light emitting metal and a rare gas are enclosed, and (2) a first electrode connected to each of the electrodes in order to apply a voltage to the light emitting tube. A high pressure discharge lamp in which a starting device having first and second electric conductors and (3) at least a filament and connected in parallel with the arc tube is arranged in an outer tube whose inside is evacuated, wherein the outer tube is A high-pressure discharge lamp, further comprising a discharge gap therein, one end of which is connected to the filament and the other end of which is connected to a conductor different from the conductor to which the filament is connected. 2. A light emitting tube comprising (1) two electrodes, wherein a light emitting metal and a rare gas are enclosed, and (2) a first electrode connected to each of the electrodes for applying a voltage to the light emitting tube. A high pressure discharge lamp in which a starting device having first and second electric conductors and (3) at least a filament and connected in parallel with the arc tube is arranged in an outer tube whose inside is evacuated, wherein the outer tube is A high-pressure discharge lamp, further comprising a discharge gap therein, the discharge gap being connected so as to melt and cut at least a part of the filament when an arc discharge occurs between the electrodes. 3. The high pressure discharge lamp according to claim 1, wherein the discharge gap holds an electron emitting material.
A high-pressure discharge lamp having a number of electrodes. 4. The high pressure discharge lamp according to claim 3,
The distance between the two electrodes of the discharge gap is 1 to 20 m
A high pressure discharge lamp having a value in the range of m. 5. The high pressure discharge lamp according to claim 1, wherein the arc tube has a proximity conductor. 6. The high pressure discharge lamp according to claim 1, wherein the starting device is a starting device in which the filament, a fixed resistor, and a thermal switch are connected in series. High-pressure discharge lamp.