JP3328121B2 - High pressure discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a high-pressure discharge lamp in which an arc tube and a starter for generating a pulse voltage for starting are built in an outer tube.

[0002]

2. Description of the Related Art As a starting circuit for a high-pressure discharge lamp having a built-in starter such as a high-pressure sodium lamp, there is conventionally known, for example, a circuit shown in FIG. The starting circuit of the first conventional high-pressure discharge lamp shown in FIG. 3 is a circuit in which a starter composed of a series circuit composed of a thermally responsive switch 9 and a heating resistor 10 is connected to the arc tube 1 in parallel. It is housed in the outer bulb of the high-pressure discharge lamp. When this high-pressure discharge lamp is connected to an AC power supply 12 via a ballast 11, the thermally responsive switch 9 repeats opening and closing operations. The ballast 11 at the moment when the thermoresponsive switch 9 opens.
Is interrupted, a pulse voltage is generated across the ballast 11. Since this pulse voltage is superimposed on the power supply voltage and applied to the arc tube 1, the arc tube 1 starts discharging. During stable operation of the high-pressure discharge lamp, the arc tube 1
The heat responsive switch 9 is kept open by the radiant heat from the switch.

However, in the first conventional high-pressure discharge lamp, the starting voltage of the luminous bulb 1 is significantly increased at the end of the life of the high-pressure discharge lamp, or the luminous bulb is discharged to the luminous bulb for some reason such as an external mechanical shock. Is disconnected, the arc tube 1 does not start, the application of the power supply voltage to the starter continues, and the pulse voltage continues to be generated. If the power switch is turned on in this state, the life of the ballast 11 can be shortened by continuous application of the pulse voltage,
There is a possibility that the insulation of the wiring between the ballast 11 and the high-pressure discharge lamp may be reduced.

In order to solve such a problem, for example, a second conventional high-pressure discharge lamp described in Japanese Patent Application Laid-Open No. 7-105913 has been proposed. The configuration is shown in FIG. In FIG. 4, a series circuit composed of a starter 14 and a first thermally responsive switch 13 is connected in parallel to the arc tube 1 and further comprises a heating resistor 15 and a thermally responsive switch 16. A series circuit is connected in parallel.
The heating resistor 15 is arranged close to the first thermally responsive switch 13. In such a configuration, when the arc tube 1 is not turned on by the pulse generated by the ballast 17 and the starter 14, the generation of the high-voltage pulse is continued, and the heating resistor 15 generates heat at the same time. 1
Is transmitted to the thermal responsive switch 13 of the
Opens. As a result, the starter 14 is disconnected from the lighting circuit, and the generation of the pulse voltage is stopped.

However, in the conventional second high-pressure discharge lamp described above, it is necessary to set both the thermoresponsive switch 13 and the thermoresponsive switch 16 to be kept open by the radiant heat from the arc tube 1 during normal operation. Also, when the high pressure discharge lamp is restarted, if the thermoresponsive switch 16 returns before the thermoresponsive switch 13, no pulse voltage is generated and the high pressure discharge lamp may not be restarted. For this reason, the thermally responsive switch 13 must be set to return before the thermally responsive switch 16, and there is a problem that the configuration of the high pressure discharge lamp is extremely difficult.

Another cause of the failure is a decrease in lamp voltage due to leakage of the arc tube 1. in this case,
At the end of the life of a high-pressure discharge lamp or the like, the hermeticity of the sealing portion of the arc tube 1 may be reduced and a rare gas for starting the arc tube 1 may flow into the vacuum outer tube. When the rare gas inside the arc tube 1 flows into the outer tube, the pressure of the rare gas in the arc tube 1 decreases, and in addition, the temperature of the arc tube 1 is increased by convection and heat conduction by the rare gas in the outer tube. descend. Therefore, the lamp voltage (operating voltage of the arc tube 1) is lower than that during normal operation. As the flow of the rare gas from the arc tube 1 progresses, the lamp voltage further decreases. When the lamp voltage decreases, the lamp current increases,
An increase in the lamp current causes an excessive temperature rise of the ballast 17. In such a state, once the power switch is turned off, and the power switch is turned on again after cooling the high-pressure discharge lamp, the arc tube 1 starts discharging again. If the high-pressure discharge lamp is left in such a state, the life of the ballast 17 may be shortened due to an increase in the temperature of the wire wound around the ballast 17.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and when the arc tube becomes unable to start for some reason or the airtightness of the arc tube sealing portion is reduced. It is an object of the present invention to provide a high-safety high-pressure discharge lamp in which a pulse voltage is not generated when a starting gas flows into an outer tube.

[0008]

In order to achieve the above object, a high-pressure discharge lamp according to the present invention comprises: a light-emitting tube having a pair of electrodes at both ends and a light-emitting substance sealed therein; A starter for applying a pulse voltage to a high-pressure discharge lamp installed in an outer bulb, wherein a series circuit including the starter and a first thermally responsive switch and a heating resistor are used to form a parallel circuit. A serial circuit comprising the parallel circuit and a second thermally responsive switch is connected in parallel to the arc tube; the first thermally responsive switch is provided near the heating resistor; After the start of the tube, the second heat responsive switch is opened by radiant heat from the arc tube , and
After the light emitting tube is turned off, the first thermoresponsive switch is turned on by the second heat switch.
Set to return before the response switch
You . In the above configuration, preferably, the second thermal reaction is performed.
The switch is more of the arc tube than the first thermoresponsive switch.
And the distance is small.

In the above structure, it is preferable that the starter is a glow starter, and a series circuit including a second thermally responsive switch and a resistor is connected in series with the parallel circuit. Alternatively, the starter is a glow starter, which is connected in series to a current limiting resistor and a current fuse element, and a discharge gap is connected in parallel to a series circuit formed by the glow starter and the current limiting resistor. preferable.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-pressure discharge lamp according to the present invention has a pair of electrodes at both ends and a light-emitting tube in which a light-emitting substance is sealed, and a starter for applying a pulse voltage between both electrodes of the light-emitting tube. Are arranged in an outer tube, a parallel circuit is formed by a series circuit including a starter and a first thermally responsive switch and a heating resistor, and configured by the parallel circuit and a second thermally responsive switch. A series circuit is connected in parallel to the arc tube, a first thermoresponsive switch is provided near the heating resistor, and after the arc tube is started, the second thermoresponsive switch is opened by radiant heat from the arc tube. Make up. Therefore, when the arc tube becomes inoperable for some reason, the current continues to flow through the heating resistor, so that the second thermally responsive element is opened and the voltage is not supplied to the starter. As a result, generation of the pulse voltage is stopped.

When a rare gas leaks from the arc tube into the outer tube, the outer tube is filled with a gas for starting the arc tube.
When an attempt is made to light a high-pressure discharge lamp, dielectric breakdown occurs between terminals of the discharge gap due to the generated high-voltage pulse. For this reason, a large current nearly equal to the short-circuit current flows through the current fuse element, and the current fuse element is destroyed. As a result, thereafter, the starter does not work and the high-pressure discharge lamp does not turn on. Therefore, it is possible to prevent the life of the ballast from being shortened due to a decrease in the lamp voltage.

(First Embodiment) Hereinafter, a first embodiment of a high-pressure discharge lamp according to the present invention will be described with reference to FIG. In the high-pressure discharge lamp shown in FIG. 1, a heating resistor 4 is connected in parallel to a series circuit composed of a starter composed of a glow starter 3 and a first thermally responsive switch 2. Further, the current limiting resistor 5 and the second
Are connected in series, and this series circuit is connected to the arc tube 1 in parallel. Each of these components is housed in the outer tube 19.

For example, when the high-pressure discharge lamp is a high-pressure sodium lamp, the arc tube 1 is filled with xenon gas as a starting gas together with sodium amalgam. The inside of the outer tube 19 is generally maintained at a high vacuum. However, in the case of a metal halide lamp, the same applies when an inert gas such as nitrogen is sealed. Here, a carbon film resistance of 300Ω is used as the current limiting resistor 5, and
As the heating resistor 4, a carbon film resistor of 30 KΩ was used. A bimetal switch having a contact pressure of 20 ± 2 g at room temperature was used as the first thermally responsive switch 2 and was installed close to the heating resistor 4 so as to have a distance of 3 mm. A bimetal switch having a contact pressure of 20 ± 2 g at room temperature was used as the second thermally responsive switch 6, and was installed so that the distance from the arc tube 1 was shorter than that of the first thermally responsive switch 2.

Next, the operation when the high-pressure discharge lamp configured as described above is turned on using the inductive ballast 7 and the power supply 8 will be described. First, when a power supply voltage is applied to the high-pressure discharge lamp via the ballast 7, the glow starter 3 starts opening / closing operation, and a pulse voltage is generated between the terminals of the ballast 7. When the discharge of the arc tube 1 is started by the pulse voltage, the arc tube voltage decreases. Therefore, the glow starter 3 stops operating, and the current flowing through the glow starter 3 also stops. At the time of stable lighting of the high-pressure discharge lamp, the heat responsive switch 6 is opened by the radiant heat from the arc tube 1, and the current supply to the heating resistor 4 is also stopped.

Next, when the high-pressure discharge lamp is restarted, the thermally responsive switch 6 is located closer to the arc tube 1 than the thermally responsive switch 2, so that the thermally responsive switch 2 returns first, and thereafter, The thermal responsive switch 6 returns. Therefore,
The voltage supply to the glow starter 3 is restarted at the same time when the thermoresponsive switch 6 returns, and the arc tube 1 restarts because the pulse voltage starts to be generated.

Next, when the arc tube 1 is in a state where it cannot be started, the arc tube 1 does not start discharging even if a power supply voltage is applied. At this time, the glow starter 3 continues to open and close, and at the same time, the heating resistor 4 continues to generate heat. Therefore, the heat responsive switch 2 is opened by the heat from the heating resistor 4. As a result, the voltage supply to the glow starter 3 is stopped, and the generation of the pulse voltage is stopped.

Second Embodiment Next, a second embodiment of the high-pressure discharge lamp of the present invention will be described with reference to FIG. In the high-pressure discharge lamp shown in FIG. 2, a heating resistor 4 is connected in parallel to a series circuit constituted by a starter constituted by a glow starter 3 and a first thermally responsive switch 2. Further, the current limiting resistor 5, the current fuse element 20 and the second thermally responsive switch 6 are connected in series to this parallel circuit, and this series circuit is connected to the arc tube 1 in parallel. Further, a discharge gap 21 is connected in parallel to a series circuit including the current limiting resistor 5, the glow starter 3, and the first thermally responsive switch 2. Each of these components
It is housed in an outer tube 19 whose inside is evacuated.

For example, when the high-pressure discharge lamp is a high-pressure sodium lamp, the arc tube 1 is filled with xenon gas as a starting gas together with sodium amalgam. The inside of the outer tube 19 is generally maintained at a high vacuum. However, in the case of a metal halide lamp, the same applies when an inert gas such as nitrogen is sealed. Here, a carbon film resistance of 300Ω is used as the current limiting resistor 5, and
As the heating resistor 4, a carbon film resistor of 30 KΩ was used. A bimetal switch having a contact pressure of 20 ± 2 g at room temperature was used as the first thermally responsive switch 2 and was installed close to the heating resistor 4 so as to have a distance of 3 mm. A bimetal switch having a contact pressure of 20 ± 2 g at room temperature was used as the second thermally responsive switch 6, and was installed so that the distance from the arc tube 1 was shorter than that of the first thermally responsive switch 2. The current fuse element 20 has a diameter of 0.2 m.
m of Monel wire, and the gap between discharge gaps was 2 mm.

The operation when the high-pressure discharge lamp configured as described above is turned on using the inductive ballast 7 and the power supply 8 and the operation at the time of restarting, and the state when the arc tube 1 cannot be started. The operation in the case of becoming the same is the same as the case of the first embodiment shown in FIG. 1, and the description thereof will be omitted.

On the other hand, when a rare gas leaks from the inside of the arc tube 1, the outer tube 19 is filled with xenon gas which is a starting gas for the arc tube 1. Therefore, when the high-pressure discharge lamp is to be turned on, dielectric breakdown occurs between the terminals of the discharge gap 21 due to the generated high-voltage pulse. For this reason, a large current almost equal to the short-circuit current flows through the current fuse element 20, and the current fuse element 20 is destroyed. Thus, thereafter, the starting device will not work and the high-pressure discharge lamp will not turn on. Therefore, it is possible to prevent the life of the ballast from being shortened due to a decrease in the lamp voltage.

[0021]

As described above, according to the high-pressure discharge lamp of the present invention, a luminous tube having a pair of electrodes at both ends and a luminous substance sealed inside, and a pulse voltage applied between both electrodes of the luminous tube. A starter for applying voltage is installed in the outer tube, and a parallel circuit is formed by a series circuit including the starter and the first thermally responsive switch and a heating resistor. A series circuit including a response switch is connected in parallel to the arc tube, a first thermal response switch is provided near the heating resistor, and a second thermal response switch is provided by radiant heat from the arc tube after starting the arc tube. Is configured to be opened. For this reason, at the end of the life of the high-pressure discharge lamp, the starting voltage of the arc tube is significantly increased, or a part of the current supply line to the arc tube is cut off due to external mechanical shock. In the inoperative state, the current continues to flow through the heating resistor to open the second thermoresponsive element, and the voltage is not supplied to the starter. As a result, generation of the pulse voltage is stopped. Therefore, there is an effect that insulation deterioration of the starter and the lighting circuit wiring can be prevented.

Further, by using a glow starter as a starter and connecting a series circuit composed of a second thermoresponsive switch and a resistor in series with a parallel circuit, the circuit configuration is simplified, and each component is simplified. At the time of mounting in the outer tube, only the positional relationship between the first thermally responsive switch and the heating resistor needs to be paid attention to, and the second thermal responsive switch should be mainly concerned with the positional relationship with the arc tube. Therefore, the number of steps for assembling the high-pressure discharge lamp can be reduced, and the mass productivity can be improved. .

Further, by adding a current fuse element and a discharge gap, when the starting rare gas in the arc tube flows into the vacuum outer tube due to a decrease in the airtightness of the sealing portion of the arc tube, etc. As a result, a discharge occurs between the electrodes of the discharge gap due to the pulse voltage at the start of the high pressure discharge lamp, a large current near the short circuit current of the ballast flows, and the current fuse is blown. As a result, the circuit of the starter is cut off, and the generation of the pulse voltage can be stopped permanently. Therefore, it is possible to prevent the ballast from failing due to a low lamp voltage due to leakage of the arc tube.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a circuit configuration of a high-pressure discharge lamp according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a circuit configuration of a high-pressure discharge lamp according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a circuit configuration of a first conventional high-pressure discharge lamp.

FIG. 4 is a schematic diagram showing a circuit configuration of a second conventional high-pressure discharge lamp.

[Explanation of symbols]

 1: arc tube 2: first thermally responsive switch 3: starter 4: heating resistor 5: current limiting resistor 6: second thermally responsive switch 7: ballast 8: power supply 9: thermally responsive switch 10: Heating resistor 11: Ballast 12: Power supply 13: Thermal response switch 14: Starter 15: Heating resistor 16: Thermal response switch 17: Ballast 18: Power supply 19: Outer tube 20: Current fuse element 21: Discharge gap

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-105913 (JP, A) JP-A-7-153432 (JP, A) JP-A-6-338295 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01J 61/54 H01J 61/56

Claims (4)

(57) [Claims] 1. A high-pressure discharge in which an arc tube having a pair of electrodes at both ends and having a light-emitting substance sealed therein and a starter for applying a pulse voltage between both electrodes of the arc tube are installed in an outer tube. A lamp, wherein a series circuit including the starter and the first thermally responsive switch and a heating resistor form a parallel circuit, and a series circuit including the parallel circuit and a second thermally responsive switch. A circuit is connected in parallel to the arc tube, and the first thermally responsive switch is provided near the heating resistor;
After starting the arc tube, the second heat responsive switch is opened by radiant heat from the arc tube, and after the arc tube is turned off,
The first thermally responsive switch is more than the second thermally responsive switch
High pressure discharge lamp set to return to the first . 2. A high-pressure discharge in which an arc tube having a pair of electrodes at both ends and a light-emitting substance sealed therein and a starter for applying a pulse voltage between both electrodes of the arc tube are installed in an outer tube. A lamp, wherein a series circuit including the starter and the first thermally responsive switch and a heating resistor form a parallel circuit, and a series circuit including the parallel circuit and a second thermally responsive switch. A circuit is connected in parallel to the arc tube, and the first thermally responsive switch is provided near the heating resistor;
And the second thermally responsive switch is connected to the first thermally responsive switch.
A high-pressure discharge lamp having a distance from the arc tube smaller than that of the switch and opening the second thermally responsive switch by radiant heat from the arc tube after starting the arc tube. 3. The starter is a glow starter,
Claim 1 or claim connected a series circuit comprised of a second thermally actuated switch in series with the resistor in the parallel circuit
2. The high-pressure discharge lamp according to 2 . 4. The starter is a glow starter,
Connected in series with current limiting resistor and a current fuse element, the glow starter and the discharge gap means the series circuit formed by the said current-limiting resistor are connected in parallel, and said outer tube is a vacuum claim 1 or The high-pressure discharge lamp according to claim 2 .