JP3558307B2 - High pressure discharge lamp - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-pressure discharge lamp.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a high-pressure discharge lamp such as a high-pressure sodium lamp, a starting rare gas such as xenon gas is sealed in an arc tube, and the efficiency is improved by increasing the sealing pressure. FIG. 3 shows a configuration of a general conventional high-pressure discharge lamp. As shown in FIG. 3, since the starting voltage of the high-pressure discharge lamp is high, a starting unit 14 composed of a series circuit of a thermally responsive switch 12 such as a bimetal switch and a resistance heating element 13 is connected in parallel with the arc tube 1, It is housed in the outer tube 4. The starting unit 14 heats the thermoresponsive switch 12 when the resistance heating element 13 glows red, and abruptly cuts off the current flowing through the ballast 10 by opening the thermoresponsive switch 12 to generate a pulse voltage.
[0003]
In the above-mentioned conventional high-pressure discharge lamp, when the starting voltage of the arc tube 1 significantly increases at the end of the life of the discharge lamp, or when the connection to the arc tube 1 is cut off for some reason such as an external mechanical shock, The arc tube 1 does not start, the application of the voltage of the power supply 11 to the starting unit 14 continues, and the pulse voltage continues to be generated. Leaving the power switch turned on in such a state may shorten the life of the ballast 10 due to the continuous application of the pulse voltage, or may cause insulation damage of the wiring between the ballast 10 and the lamp 1. .
[0004]
Therefore, in another conventional high-pressure discharge lamp disclosed in, for example, JP-A-7-105913, as shown in FIG. A switch 22 is connected in series, and a series circuit including a resistance heating element 20 and a thermally responsive switch 21 is connected in parallel to the arc tube 1 and the starting unit 14. The resistance heating element 20 and the thermally responsive switch 22 are arranged close to each other. In the configuration shown in FIG. 4, when the arc tube 1 does not start, the heat-responsive switch 22 disposed close to the heat-generating switch 22 is opened by the heat generated by the resistance heating element 20, and the application of the voltage to the starting unit 14 is stopped.
[0005]
[Problems to be solved by the invention]
However, the circuit configuration shown in FIG. 4 does not permanently disable the starting unit 14 when the arc tube 1 cannot be started. When the application of the power supply voltage to the discharge lamp is stopped, the heat responsive switch 22 Returns to its original state. Therefore, when the power is turned on again, the generation of the pulse voltage for a certain period is repeated, thereby shortening the life of the ballast 10 due to the application of the pulse voltage and causing insulation damage of the wiring between the ballast 10 and the lamp 1. Problem is not solved.
[0006]
The present invention has been made in order to solve the problems of the above-described conventional example, and when the arc tube does not start for some reason, the starting unit is destroyed to make the operation tube permanently inoperable, whereby the pulse voltage is reduced. It is an object of the present invention to provide a high-safety high-pressure discharge lamp that does not generate any gas.
[0007]
[Means for Solving the Problems]
To achieve the above object, the high-pressure discharge lamp of the present invention, housed in the outer tube a series circuit including a glow starter, a thermo-switch of the resistance heating element and a normally closed connected in parallel to the arc tube, said thermal responsive The thermal responsive switch is installed at a position where the operating temperature of the switch is within a range of 100 to 350 ° C. and the temperature of the glow starter reaches the operating temperature after the temperature of the glow starter reaches 600 ° C. or more due to heat from the resistance heating element. and, when the arc tube is not operating, the glow starter by the heat of the resistance heating element has been configured to so that is destroyed.
In the above SL configuration, the resistance heating element is preferably a ceramic heater.
In the above configuration, it is preferable that the resistance heating element has a cold resistance value of 100Ω to 500Ω.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The high pressure discharge lamp of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a circuit configuration of the high-pressure discharge lamp of the first embodiment, and FIG. 2 is a diagram showing an example of a device arrangement of a series body composed of a glow starter, a resistance heating element and a thermally responsive switch. is there.
[0009]
As shown in FIG. 1, in the high-pressure discharge lamp of the present invention, a starting unit 2 composed of a series circuit of a glow starter 7, a resistance heating element 8, and a thermally responsive switch 3 connects an electrode 1 a and an electrode 1 b of an arc tube 1. They are connected in parallel between them and housed in the outer tube 4. When the high-pressure discharge lamp is a high-pressure sodium lamp, the inside of the outer tube 4 is generally maintained at a high vacuum. On the other hand, when the high-pressure discharge lamp is a metal halide lamp, the outer tube 4 may be filled with an inert gas such as nitrogen. One electrode 1 a of the arc tube 1 is connected to a starting auxiliary conductor 5 via a starting auxiliary heat responsive switch 6. The starting auxiliary conductor 5 is wound along the outer surface of the arc tube 1 and is provided near the arc tube 1. Both electrodes 1 a and 1 b of the arc tube 1 are connected to a power supply 11 via a ballast 10.
[0010]
The starting unit 2 includes a glow starter 7, a resistance heating element 8 for limiting a current flowing through the glow starter 7, and a supply of current to the glow starter 7 and the resistance heating element 8 after the arc tube 1 starts discharging. Of the thermoresponsive switch 3. The return time of the thermally responsive switch 3 is longer than the return time of the start-assisting thermally responsive switch 6 when the lamp is restarted, that is, when the current to the lamp is shut off and turned on again. It is set to be. FIG. 2 shows the arrangement of the equipment constituting the starting unit 2. As shown in FIG. 2, the glow starter 7 is in contact with the resistance heating element 8. In addition, the thermally responsive switch 3 is provided at a position where it operates by heat from the resistance heating element 8 when the temperature of the glow starter 7 becomes equal to or higher than the bulb heat resistance when the arc tube 1 is not operated.
[0011]
Next, the operation when the high-pressure discharge lamp of the present invention is turned on by using the inductive ballast 10 and the power supply 11 will be described. First, when a power supply voltage is applied to the high-pressure discharge lamp via the ballast 10, a current flows through the starting unit 2. When the glow starter 7 of the starting unit 2 performs the opening / closing operation, a sudden change in the current flowing through the ballast 10 occurs, and a pulse voltage is induced in the ballast 10. Then, the discharge of the arc tube 1 is started by the pulse voltage and the starting auxiliary effect of the starting auxiliary conductor 5 provided on the outer surface of the arc tube 1. After the start of the discharge, the heat responsive switch 6 and the heat responsive switch 3 are opened by the heat from the arc tube 1, and the voltage application to the starting auxiliary conductor 5 and the starting unit 2 is stopped.
[0012]
In a state where the arc tube 1 operates normally, the time from application of the power supply voltage to the start of the discharge of the arc tube 1 is several seconds at the longest, and the heating by the resistance heating element 8 during this period is not performed. Even if it receives, the glow starter 7 does not reach the closed circuit temperature. However, at the end of the life of the lamp, the starting voltage of the arc tube 1 rises significantly, or a part of the current supply line to the arc tube 1 is cut off by an external mechanical shock. When the start is impossible, the arc tube 1 does not start discharging even when the power supply voltage is applied, the glow starter 7 continues to open and close, and the current continues to flow intermittently in the circuit of the start unit 2. The temperature of the resistance heating element 8 increases. Thus, the glow starter 7 is heated. When the temperature of the glow starter exceeds the operating temperature of the bimetal contact attached to the glow starter 7, the glow starter 7 is normally closed. Therefore, the current interruption is eliminated, and the generation of the pulse voltage by the ballast 10 is stopped. Thereafter, by applying a voltage to the resistance heating element 8, heating from the resistance heating element 8 to the glow starter 7 continues.
[0013]
When the temperature of the glow starter 7 exceeds the allowable temperature limit of the valve of the glow starter 7, the valve of the glow starter 7 leaks. Thereafter, the thermoresponsive switch 3 is opened, the current to the starting unit 2 is cut off, the temperature of the ceramic heater 7 returns to the normal temperature, and the thermoresponsive switch 3 is closed. However, even if the bimetal contact of the glow starter 7 is opened, the glow discharge does not occur in the glow starter 7 because the gas filled in the glow starter 7 is released, and the ballast 10 generates a pulse voltage twice. do not do.
[0014]
【Example】
Next, specific examples of the present invention will be described. A 220 W high-pressure sodium lamp was produced with the circuit configuration shown in FIG. The dimensions of the arc tube 1 are 9 mm in outer diameter and 58 mm between electrodes. The glow starter 7 used had an operating temperature of the bimetal contact of about 100 ° C. and a heat-resistant temperature of the valve of about 550 ° C. As the resistance heating element 8 connected in series to the glow starter 7, a square ceramic heater having a side of 25 mm was used. The resistance value (cold resistance value) at room temperature of the ceramic heater was about 100Ω, and the resistance value at a saturation temperature of about 500 ° C. was about 500Ω. A bimetal switch having an operating temperature of about 200 ° C. was used as the thermally responsive switch 3.
[0015]
When the high-pressure sodium lamp thus manufactured was connected to a 200 V AC power supply via a 250-W high-pressure mercury lamp ballast, the arc tube 1 started normally through the above-described process and shifted to a stable state. Next, in order to perform an experiment in a state in which the arc tube 1 cannot be started, the discharge lamp is turned off and cooled, and then the arc tube is used in the outer tube 4 without breaking the outer tube 4 using a laser beam. The current supply line to the light-emitting tube 1 was cut off, so that the arc tube 1 could not be started. When the power supply voltage is applied in this state, the current continues to flow through the starting unit 2, the temperature of the ceramic heater as the resistance heating element 8 rises rapidly, and the heating from the ceramic heater 8 to the glow starter 7 continues, and the glow starter The temperature of 7 exceeded the operating temperature of the bimetal contact attached to glow starter 7, and glow starter 7 was closed. Further, when the temperature of the glow starter 7 exceeded the heat-resistant temperature of the valve of the glow starter 7, the valve leaked, the sealed gas inside was released, and the glow starter 7 was destroyed. Thereafter, the thermoresponsive switch 3 was opened. As a result, the circuit of the starting unit 2 was cut off, and the generation of the pulse voltage from the ballast 10 was stopped. Further, since the glow starter 7 was destroyed, no pulse voltage was generated again.
[0016]
Here, the cold resistance value of the resistance heating element 8 is set to about 100Ω. However, if the cold resistance value is 100Ω or less, the current flowing through the starter 2 is large, so that the deterioration of the glow starter 7 becomes very fast. On the other hand, when the resistance is 500Ω or more, a sufficient current for starting the arc tube 1 cannot be obtained because the current flowing through the starter 2 is small. Therefore, a range of about 100 to 500Ω is appropriate for practical use.
[0017]
Furthermore, although the operating temperature of the thermoresponsive switch 3 is set to about 200 ° C., the ambient temperature when the lamp is actually used is at most about 50 ° C. at most, and in this case, the thermoresponsive switch 3 is surely closed. Need to be. Further, the heat responsive switch 3 must be arranged so as not to hinder the light emission when the lamp is turned on. Furthermore, in order to stop the current supply to the starter 2 when the lamp is turned on, it is necessary to open the thermoresponsive switch 3 reliably. Taking these into consideration, it is sufficient in practice to be within the range of about 100-350 ° C.
[0018]
In the above embodiment, the high pressure sodium lamp has been described, but the same effect can be obtained with a metal halide lamp.
[0019]
【The invention's effect】
As described above, in the high-pressure discharge lamp of the present invention, a series circuit including a glow starter, a resistance heating element, and a normally-closed thermoresponsive switch is connected in parallel to the arc tube and housed in the outer tube, and the arc tube does not operate. In this case, the glow starter is configured to be destroyed by the heat of the resistance heating element. Therefore, even when the arc tube does not start for some reason, current continues to flow intermittently to the starting unit due to the opening / closing operation of the glow starter, the temperature of the resistance heating element rises, and the glow starter is heated. When the temperature of the glow starter exceeds the operating temperature of the bimetal contact attached to the glow starter, the glow starter is normally closed. Therefore, current interruption is eliminated, and generation of a pulse voltage by the ballast is stopped. However, after that, the voltage is applied to the resistance heating element, the heating of the glow starter from the resistance heating element continues, and when the temperature of the glow starter exceeds the heat resistant temperature of the glow starter valve, the glow starter valve leaks. , The internal gas is released. After that, the thermoresponsive switch is opened, the current to the starting unit is cut off, the temperature of the ceramic heater returns to normal temperature, and even if the thermoresponsive switch is closed, the filled gas in the glow starter is released, No glow discharge occurs in the glow starter, and the ballast does not generate a pulse voltage twice. Therefore, it is possible to provide a high-safety high-pressure discharge lamp that is free from electric shock when the lamp is replaced.
[0020]
Further, the switching temperature of the thermoresponsive switch is set in the range of 100 to 350 ° C., and after the temperature of the glow starter becomes 600 ° C. or more due to the heat from the resistance heating element, the thermoresponsive switch is located at a position where the operating temperature is reached. By installing the glow starter, the glow starter can be reliably broken without the thermal responsive switch being circuited before the glow starter valve leaks.
[0021]
Further, by using a ceramic heater as the resistance heating element, a resistance value of about 100Ω at room temperature and about 500Ω at a saturation temperature of about 500 ° C can be obtained. Further, the resistance heating element can be reduced in size, and does not hinder light emission when the lamp is turned on. Further, by setting the cold resistance value of the resistance heating element in the range of 100 to 500Ω, a pulse voltage sufficient to start the arc tube can be obtained, and the glow starter does not rapidly deteriorate. Further, by making the distance from the resistance heating element to the thermal responsive switch longer than the distance from the resistance heating element to the glow starter, the glow starter can be closed earlier than the thermal responsive switch is opened.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a circuit configuration of one embodiment of a high-pressure discharge lamp of the present invention. FIG. 2 is a layout diagram of components of a starting unit in one embodiment of a high-pressure discharge lamp of the present invention. FIG. 4 is a schematic diagram showing a circuit configuration of a high-pressure discharge lamp. FIG. 4 is a diagram showing a circuit configuration of another conventional high-pressure discharge lamp.
1: arc tube 2: starting unit 3: thermal response switch 4: outer tube 5: starting auxiliary conductor 6: thermal activation switch 7 for starting assistance: glow starter 8: resistance heating element 9: resistor 10: ballast 11: power supply 12: Bimetal switch 13: Heating resistor 14: Starting unit

Claims (3)

A series circuit including a glow starter, a resistance heating element, and a normally-closed thermoresponsive switch is connected in parallel to the arc tube and housed in an outer tube, and an operating temperature of the thermoresponsive switch is in a range of 100 to 350 ° C; The thermal responsive switch is installed at a position where the temperature of the glow starter reaches the operating temperature after the temperature of the glow starter reaches 600 ° C. or more due to heat from the resistance heating element. high-pressure discharge lamp in which the glow starter is Ru destroyed by body heat. The resistance heating element is a ceramic heater according to claim 1 Symbol mounting the high-pressure discharge lamp. The cold resistance of the resistance heating element is 100Ω~500Ω claim 1 or 2 high-pressure discharge lamp as claimed.

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