JP3701060B2 - High pressure discharge lamp - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high pressure discharge lamp.
[0002]
[Prior art]
Conventionally, in a high-pressure discharge lamp such as a high-pressure sodium lamp, the efficiency is improved by enclosing a starting rare gas such as xenon gas in an arc tube and increasing the sealing pressure. Since the starting voltage of the high-pressure discharge lamp is high, for example, as shown in FIG. 4, a starter 14 composed of a series circuit of a bimetal switch 12 and a heating resistor 13 is connected in parallel with the arc tube 1, and the outer tube 4 Is housed inside. In the starter 14, the heating resistor 13 is heated red to heat the bimetal switch 12, and when the bimetal switch 12 is opened, the current flowing through the ballast 10 is rapidly cut off to generate a pulse voltage.
[0003]
[Problems to be solved by the invention]
In the conventional high-pressure discharge lamp, when the starting voltage of the arc tube is significantly increased at the end of the life of the discharge lamp, or when the connection to the arc tube is cut for some reason such as mechanical shock from the outside, the arc tube Does not start, the power supply voltage continues to be applied to the starting unit, and the pulse voltage continues to be generated. If the power switch is left turned on in such a state, the life of the ballast may be shortened by continuously applying the pulse voltage, or the insulation of the wiring between the ballast and the lamp may be lowered.
[0004]
The present invention has been made to solve the above-described problems of the conventional example, and an object of the present invention is to provide a high-safety high-pressure discharge lamp that does not generate a pulse voltage when the arc tube does not start for some reason. It is said.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a high-pressure discharge lamp according to the present invention includes a series circuit including a glow starter, a resistance heating element, and a normally closed thermal responsive switch connected in parallel to an arc tube and accommodated in an outer tube. After the start of the discharge, the heat responsive switch is opened by heat from the arc tube, and when the arc tube is inoperative, the contact of the glow starter is closed by the heat of the resistance heating element, and thermo-switch is a high-pressure discharge lamp for holding the closing switching temperature of the heat-switch is in the range of 100 to 350 ° C., in between the heat-actuated switch and the resistance heating element, the resistance thermally the heat-switch hinders from the heating element is at a position of less susceptible to heat, prior to the heat temperature is 0.99 ° C. or more positions from the resistance heating element when the arc tube is inoperative It is obtained by installing the glow starter.
In the above configuration, the resistance heating element is preferably a ceramic heater.
In the above configuration, the resistance heating element preferably has a cold resistance value of 100Ω to 500Ω.
[0006]
DETAILED DESCRIPTION OF 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 a high-pressure discharge lamp according to a first embodiment, and FIG. 2 is a front view showing a configuration of a main part of the high-pressure discharge lamp.
[0007]
As shown in FIG. 1, in the high-pressure discharge lamp of the present invention, a series circuit composed of a starter 2 and a thermally responsive switch 3 is connected in parallel between both electrodes 1a and 1b of an arc tube 1, and an outer tube 4 It is stored inside. When the high-pressure discharge lamp is a high-pressure sodium lamp, 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, an inert gas such as nitrogen may be enclosed in the outer tube 4. One electrode 1 a of the arc tube 1 is connected to the starting auxiliary conductor 5 via the starting auxiliary thermal responsive switch 6. The starting auxiliary conductor 5 is wound along the outer surface of the arc tube 1 and is provided close to the arc tube 1. Both electrodes 1 a and 1 b of the arc tube 1 are connected to a power source 11 via a ballast 10.
[0008]
The starter 2 is composed of a series circuit of a glow starter 7 and a resistance heating element 8 for limiting the current flowing through the glow starter 7. The thermally responsive switch 3 stops the supply of current to the starter 2 after the discharge of the arc tube 1 is started. The return time of the heat responsive switch 3 is longer than the return time of the start assist heat responsive switch 6 in order to ensure lighting when the lamp is restarted, that is, when the current to the lamp is interrupted and turned on again. It is set to be. The arrangement of the starter 2 and the thermally responsive switch 3 is shown in FIG. As shown in FIG. 2, the glow starter 7 is in contact with the resistance heating element 8, and the thermally responsive switch 3 is disposed above the glow starter 7 so that it is difficult to receive heat from the resistance heating element 8.
[0009]
Next, FIG. 3 shows a configuration example when the arc tube 1 having an auxiliary electrode is used. The configuration example shown in FIG. 1 is that the starting auxiliary conductor 5 and the starting auxiliary heat responsive switch 6 are not provided, and the resistor 9 for suppressing the current to the auxiliary electrode is the electrode 1b of the arc tube 1. When, that is provided between the connection point of the starter 2 and thermo-switch 3 is different.
[0010]
Next, the operation when the high pressure sodium lamp of the present invention is lit using the inductive ballast 10 and the power source 11 will be described. First, when a power supply voltage is applied to the high-pressure sodium lamp having any one of the above configurations via the ballast 10, a current flows through the starter 2. When the glow starter 7 of the starter 2 performs an opening / closing operation, a sudden change in the current flowing in 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 start assist effect of the start assist conductor 5 provided on the outer surface of the arc tube 1. After the start of discharge, the heat assisting switch 6 for starting assistance and the heat acting switch 3 are opened by the heat from the arc tube 1, and voltage application to the starting assistant conductor 5 and the starter 2 is stopped.
[0011]
In a state in which the arc tube 1 is operating normally, the time from the application of the power supply voltage to the start of the discharge of the arc tube 1 is a few seconds at most, and heating by the resistance heating element 8 during this period is performed. Even if received, the glow starter 7 does not reach the closed circuit temperature. However, due to troubles such as the starting voltage of the arc tube 1 significantly increasing at the end of the lamp life or a part of the current supply line to the arc tube 1 being cut off due to a mechanical impact from the outside, the arc tube 1 is When the engine cannot be started, 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 of the starter 2 continues to flow intermittently. The temperature of the resistance heating element 8 increases. Thereby, the glow starter 7 is heated. When the temperature of the glow starter exceeds the closing temperature of the contact attached to the glow starter 7, the glow starter 7 is always closed. Therefore, there is no sudden change in current, and generation of the pulse voltage by the ballast 10 stops.
[0012]
【Example】
Next, specific examples of the present invention will be described. The circuit configuration shown in FIG. 1 was arranged as shown in FIG. 2 to produce a 220 W high pressure sodium lamp. The dimensions of the arc tube 1 are an outer diameter of 9 mm and a distance between electrodes of 58 mm. The closing temperature of the contact point of the glow starter 7 is about 100 ° C., and the heat resistance temperature of the valve is 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 30 mm was used. The resistance value of the ceramic heater at room temperature was about 100Ω, and the resistance value at a saturation temperature of about 500 ° C. was about 500Ω. In addition, a bimetal switch having an open circuit temperature of about 200 ° C. was used as the thermally responsive switch 3 connected in series to the starter 2 composed of these components.
[0013]
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, since the current flowing through the starter 2 is large, the deterioration of the glow starter 7 becomes very fast. On the other hand, in the case of 500Ω or more, since the current flowing through the starter 2 is small, a pulse voltage sufficient to start the arc tube 1 cannot be obtained. Therefore, a range of about 100 to 500Ω is suitable for practical use.
[0014]
Furthermore, although the open circuit temperature of the heat responsive switch 3 is about 200 ° C., the ambient temperature when the lamp is actually used is at most about 50 ° C. In this case, the heat responsive switch 3 is reliably closed. Need to be. In addition, the thermally responsive switch 3 must be arranged so as not to disturb the light emission when the lamp is lit. Furthermore, since the current supply to the starter 2 is stopped when the lamp is lit, it is necessary to reliably open the heat responsive switch 3. Taking these into consideration, it is sufficient in practice to be within a range of about 100 to 350 ° C.
[0015]
By widening the contact interval of the glow starter 7, the operating temperature of the contact can be raised and a high pulse voltage can be obtained. However, along with this, the operating voltage of the glow starter 7 increases and the performance decreases. For this reason, the operating temperature of the contact is set to about 100 ° C. which is optimum for practical use. In order to securely close the contact, the glow starter 7 may be installed at a position where the temperature is 150 ° C. or higher.
[0016]
When the high-pressure sodium lamp manufactured according to the above specifications was connected to a 200 V AC power source via a 250 W high-pressure mercury lamp ballast, the arc tube 1 was installed within a few seconds after the power was turned on through the process described above. The system started normally and shifted to a stable lighting state. Next, in order to conduct an experiment in a state in which the arc tube 1 cannot be started, after the lamp is turned off and cooled, the arc tube is used in the outer tube 4 without destroying the outer tube 4 by using a laser beam. The current supply line to 1 was cut, and the arc tube 1 was made unstartable. When the power supply voltage was applied in this state, the current continued to flow through the starter 2, the temperature of the ceramic heater rapidly increased, and the contact of the glow starter 7 was closed after about 30 seconds, and the generation of the pulse voltage was stopped. That is, it was confirmed that the high pressure discharge lamp of the present invention operates according to the intended purpose.
[0017]
【The invention's effect】
As described above, according to the present invention, in the outer tube, together with the arc tube, a series body including a glow starter, a resistance heating element, and a normally closed thermally responsive switch is connected and accommodated in parallel to the arc tube. In the unlikely event that the starting voltage of the arc tube rises significantly at the end of the lamp's life, or an accident such as the disconnection of a part of the current supply line to the arc tube due to an external mechanical shock, the arc tube cannot be started. Even in this state, since the glow starter is closed by the heat of the resistance heating element and the thermal responsive switch is also closed, there is no sudden change in current, and generation of the pulse voltage by the ballast stops. As a result, it is possible to prevent the insulation of the ballast and the lighting circuit wiring from being lowered, and a high-safety high-pressure discharge lamp can be obtained.
[0018]
Further, when the glow starter is closed by setting the switching temperature of the heat responsive switch within the range of 100 to 350 ° C. and installing the glow starter at a position where the temperature becomes 150 ° C. or more by the heat from the resistance heating element, The heat responsive switch can be closed reliably. In addition, since the current supply to the starter is stopped when the lamp is lit, the heat responsive switch can be reliably opened.
[0019]
Moreover, by using a ceramic heater as the resistance heating element, a resistance value of about 100Ω at room temperature and a saturation value of about 500Ω at a saturation temperature of about 500 ° C. can be obtained. In addition, 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 is not rapidly deteriorated. In addition, by placing a glow starter between the resistance heating element and the thermal activation switch, the glow starter prevents heat from the resistance heating element, making the thermal activation switch less susceptible to heat and being normally closed. Can keep the state of.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a circuit configuration of an embodiment of a high-pressure discharge lamp according to the present invention. FIG. 2 is a front view showing an arrangement of main components in an embodiment of the high-pressure discharge lamp of the present invention. FIG. 4 is a schematic diagram showing the circuit configuration of another embodiment of the high-pressure discharge lamp of the invention. FIG. 4 is a schematic diagram showing the circuit configuration of a conventional high-pressure discharge lamp.
1: Arc tube 2: Starter 3: Thermally responsive switch 4: Outer tube 5: Starter auxiliary conductor 6: Starter auxiliary thermally responsive switch 7: Glow starter 8: Resistance heating element 9: Resistor 10: Ballast 11: Power supply 12: Bimetal switch 13: Heating resistor 14: Starter

Claims (3)

A series circuit including a glow starter, a resistance heating element, and a normally closed thermally responsive switch is connected in parallel to the arc tube, accommodated in the outer tube, and after the discharge of the arc tube is started, the heat is generated by the heat from the arc tube. When the responsive switch is opened and the arc tube is inoperative, the contact of the glow starter is closed by the heat of the resistance heating element, and the thermal responsive switch is a high pressure discharge lamp that is kept closed. ,
The switching temperature of the thermally responsive switch is in the range of 100-350 ° C;
A position between the resistance heating element and the heat responsive switch that prevents heat from the resistance heating element and makes the heat responsive switch difficult to receive heat, and the resistance when the arc tube is inoperative. A high-pressure discharge lamp in which the glow starter is installed at a position where the temperature becomes 150 ° C. or higher due to heat from a heating element.   The high-pressure discharge lamp according to claim 1, wherein the resistance heating element is a ceramic heater.   The high-pressure discharge lamp according to claim 1 or 2, wherein the resistance heating element has a cold resistance value of 100Ω to 500Ω.

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